WO2017070949A1 - Signal processing device and method in optical communication systems - Google Patents

Abstract

The present invention provides a device and a method for processing signals in optical communication systems, the device comprising: a signal processing module for performing digital signal processing on two digital signals to output a first real signal, a first imaginary signal, a second real signal and a second imaginary signal; an arithmetic module for adding and/or subtracting the two real signals outputted by the processing module, and outputting a first operation signal and a second operation signal; A digital-analog conversion module for digital-analog conversion of the two operation signals to obtain two analog signals; and a single polarization electro-optical modulator for realizing single sideband modulation to output a single sideband modulation signal, wherein the two sideband of the spectrum of the single sideband modulation signal carries the data of the two digital signals respectively. The invention realizes single sideband modulation by using a single polarization electro-optical modulator, and can effectively reduce the system cost.

Description

Apparatus and method for processing signals in an optical communication system Technical field

The present invention relates to the field of communications and, more particularly, to an apparatus and method for processing signals in an optical communication system.

Background technique

In recent years, short-distance optical communication has grown rapidly, and the growth rate will further accelerate with the continuous development of the mobile Internet. For short-range optical communications, device cost and power consumption are major considerations. In long-distance optical communication, coherent systems have good performance and mature technology, but because of the high cost and power consumption, they are not suitable for short-distance applications. Therefore, in short-range optical communication applications, people pay more attention to Intensity Modulation/Direct Detection ("IM/DD") technology. In the prior art, when implementing IM/DD, two digital signals are respectively modulated on two orthogonal polarization states of an optical carrier by a bipolar electro-optical modulator at a transmitter, and the optical carrier is transmitted to a receiver through an optical fiber. Therefore, in the signal obtained after the optical carrier passes through the beat processing of the photodiode of the receiver, the signal and signal beat interference ("SSBI") of the signal and the signal may fall within the same guard band. This can improve signal performance.

However, the above scheme requires the use of a bipolar electro-optic modulator at the transmitter, and the device cost is high.

Summary of the invention

Embodiments of the present invention provide an apparatus for processing signals in an optical communication system, which can reduce system cost.

In a first aspect, there is provided an apparatus for processing a signal in an optical communication system, the optical communication system for processing a first digital signal and a second digital signal, the apparatus comprising: a signal processing module for the first The digital signal is digitally processed to output a first real signal and a first imaginary signal, and the second digital signal is digitally processed to output a second real signal and a second imaginary signal, wherein the first real signal and The frequency of the first imaginary signal falls within the intermediate frequency X/2 portion of the bandwidth of the optical communication system, and the frequencies of the second real signal and the second imaginary signal fall into the high frequency X/2 portion of the bandwidth of the optical communication system Where 1/2 ≤ X ≤ 2/3, the first imaginary signal is a Hilbert transform of the first real signal, and the second imaginary signal is a Hilbert of the second real signal And an operation module, configured to perform a first operation on the first real number signal and the second real number signal output by the signal processing module, to obtain a first operation signal, and output the first imaginary number signal to the signal processing module The second imaginary signal performs a second operation to obtain a second operation signal, wherein the first operation is an addition operation and the second operation is a subtraction operation, or the first operation is a subtraction operation and the second operation is an addition operation; The digital-to-analog conversion module is configured to perform digital-to-analog conversion on the first operational signal to obtain a first analog signal, and perform digital-to-analog conversion on the second operational signal to obtain a second analog signal; and a single-bias electro-optic modulator for receiving The first analog signal or the amplified signal of the first analog signal, and the amplified signal of the second analog signal or the second analog signal, and electro-optic modulated to obtain a single sideband modulated signal of the optical domain, wherein the single side The sidebands of the spectrum with the modulated signal carry the data of the first digital signal and the second digital signal, respectively.

In the embodiment of the present invention, the arithmetic operation of the real part and the imaginary part of the two digital signals is performed separately, and the result of the operation is used as two inputs of a single-bias electro-optic modulator, and the spectrum of the single sideband modulated signal thus obtained is obtained. The two sidebands respectively carry the data of the two digital signals, thereby eliminating the need to separately modulate two digital signals by using a bipolar electro-optic modulator, which can save cost.

In other words, the embodiment of the present invention does not directly input the digital electrical signal into the bipolar electro-optic modulator, but first performs pre-processing based on two electrical signals, that is, performs arithmetic operations on the real and imaginary parts of the two electrical signals, The preprocessed signal obtained after the operation is used as the input of the single-bias electro-optic modulator, so that only one single-bias electro-optic modulator can realize the modulation of the two digital electrical signals. The double-bias modulator can be implemented by two single-bias modulators, wherein the polarization states of the two single-bias modulators are orthogonal to each other, or can also be a specially designed modulator with two orthogonally-biased normals, no matter which In the form of a double-bias modulator, the device cost is high, and the embodiment of the invention only needs a single-bias modulator, which reduces the system cost.

With reference to the first aspect, in a first implementation manner of the first aspect, the X=2/3, wherein a frequency of the first real number signal and the first imaginary number signal falls within an intermediate frequency of the bandwidth of the optical communication system. In part 3, the frequencies of the second real number signal and the second imaginary number signal fall within a high frequency 1/3 portion of the bandwidth of the optical communication system.

In the embodiment of the present invention, the frequency of the first real number signal and the first imaginary number signal falls into the intermediate frequency 1/3 portion of the bandwidth of the optical communication system, and the frequencies of the second real number signal and the second imaginary number signal fall into the light. The high-frequency 1/3 portion of the bandwidth of the communication system, such that only 1/3 of the low-frequency portion of the obtained single-sideband modulated signal is not used to transmit data as a guard band for accommodating SSBI, so that 2/3 can be utilized. The spectrum resources achieve good system resource utilization while improving signal performance.

With reference to the first aspect or the foregoing implementation manner, in a second implementation manner of the first aspect, the single-polarization optical modulator includes an optical input port, an optical output port, a first radio frequency port, a second radio frequency port, and multiple DCs a biasing port for inputting a continuous optical signal, the first RF port is configured to input the first analog signal or an amplified signal of the first analog signal, and the second RF port is configured to input the second analog a signal or an amplified signal of the second analog signal, the plurality of DC bias ports are respectively for inputting a DC bias voltage, and the light output port is configured to output the single sideband modulated signal.

The single-bias electro-optic modulator electro-optically modulates the signals input to the optical input port, the first RF port, and the second RF port according to the DC bias voltage to obtain a single-sideband modulated signal of the optical domain, and outputs the light through the light The port outputs the single sideband modulated signal, wherein the sidebands of the spectrum of the single sideband modulated signal respectively carry data of the first digital signal and the second digital signal.

In combination with the first aspect or the foregoing implementation manner, in a third implementation manner of the first aspect, the single-polarization optical modulator is a quadrature IQ modulator, wherein the first radio frequency port is an I port of the IQ modulator And the second RF port is a Q port of the IQ modulator, or the first RF port is a Q port of the IQ modulator and the second RF port is an I port of the IQ modulator, the multiple DC biases The port includes a first bias port corresponding to the I port, a second bias port corresponding to the Q port, and a third bias port, wherein a DC bias of the first bias port is set at 0.75π, The DC bias of the second bias port is set at 0.75π, and the DC bias of the third bias port is set at 0.5π.

By setting the three DC biases of the IQ modulator, the embodiment of the present invention can perform an electro-optic modulation operation using a commonly used IQ modulator, wherein the pre-processed real and imaginary signals are respectively used as I of the IQ modulator. Q two-way input, this implementation is relatively simple and easy.

With reference to the first aspect or the foregoing implementation manner, in a fourth implementation manner of the first aspect, the single-polarization optical modulator is a parallel two-electrode Mach-Zehnder modulator DD-MZM, wherein the first RF port is the The upper arm RF input port of the DD-MZM and the second RF port is the DD-MZM lower arm RF input port, or the first RF port is the lower arm RF input port of the DD-MZM and the second RF port is the a DD-MZM upper arm RF input port, the plurality of DC bias ports including a first bias port corresponding to the upper arm RF input port, and a second bias port corresponding to the lower arm RF input port, wherein the A bias port is grounded, and the DC bias of the second bias port is set at 0.25 π.

By setting the two DC biases of the DD-MZM, the embodiment of the present invention can perform the electro-optic modulation operation using the commonly used DD-MZM, wherein the pre-processed real and imaginary signals are respectively performed. For the DD-MZM's upper and lower arm inputs, this implementation is relatively simple and easy.

With reference to the first aspect or the foregoing implementation manner, in a fifth possible implementation manner of the first aspect, the electrical domain of the first real number signal, the first imaginary number signal, the second real number signal, and the second imaginary number signal The modulation mode is Direct Multi-tone Technology ("DMT") modulation or Carrier-less Amplitude Phase ("CAP") modulation.

In order to facilitate signal transmission and processing, in the above digital signal processing of the electrical domain, electrical domain modulation processing (for example, quadrature amplitude mapping) may be included before the electro-optic modulation is performed, thereby obtaining the real signal and the imaginary signal. The embodiment of the present invention does not limit the electrical domain modulation mode of the real number signal and the imaginary number signal, and may be the above DMT modulation or CAP modulation. These modulation methods are relatively mature and easy to use, but other suitable modulation methods may also be used.

With reference to the first aspect or the foregoing implementation manner, in a sixth possible implementation manner of the first aspect, the first digital signal and the second digital signal are pseudo random binary sequences (Pseudorandom binary sequence, referred to as “PRBS” ")Digital signal. This PRBS signal is a common data format in communication and is convenient for simulating random codes in real systems.

In combination with the first aspect or the foregoing implementation manner, in the seventh possible implementation manner of the first aspect, the signal processing module, the computing module, and the digital-to-analog conversion module may be a digital signal processor (DSP) ")achieve. This method requires only one DSP, which saves equipment space and reduces costs. Of course, the embodiments of the present invention may also implement these modules in other manners. For example, the signal processing module can be implemented by a DSP or a dedicated chip, the arithmetic module can be implemented by an adder circuit and a subtractor, and the digital-to-analog conversion module can be implemented by an Analog-Digital Converter ("ADC").

In a second aspect, a method for processing a signal in an optical communication system for processing a first digital signal and a second digital signal is provided, the method comprising: performing a digital signal on the first digital signal Processing to output a first real number signal and a first imaginary number signal, performing digital signal processing on the second digital signal to output a second real number signal and a second imaginary number signal, wherein the first real number signal and the first imaginary number signal are The frequency falls within the intermediate frequency X/2 portion of the bandwidth of the optical communication system, and the frequencies of the second real signal and the second imaginary signal fall into the high frequency X/2 portion of the bandwidth of the optical communication system, where 1/2 ≤ X ≤ 2/3, the first imaginary signal is a Hilbert transform of the first real signal, and the second imaginary signal is a Hilbert transform of the second real signal; the output of the signal processing module The first real number signal and the second real number signal perform a first operation to obtain a first operation Calculating a signal, performing a second operation on the first imaginary signal and the second imaginary signal output by the signal processing module to obtain a second operation signal, where the first operation is an addition operation and the second operation is a subtraction operation, or The first operation is a subtraction operation and the second operation is an addition operation; performing digital-to-analog conversion on the first operation signal to obtain a first analog signal, and performing digital-to-analog conversion on the second operation signal to obtain a second analog signal; Single sideband modulation by a single-bias electro-optic modulator, wherein the single-bias electro-optic modulator is configured to receive the first analog signal or an amplified signal of the first analog signal, and the second analog signal or the second analog signal The signal is amplified and electro-optic modulated to obtain a single sideband modulated signal of the optical domain, wherein the sidebands of the spectrum of the single sideband modulated signal respectively carry data of the first digital signal and the second digital signal.

In the embodiment of the present invention, the arithmetic operation of the real part and the imaginary part of the two digital signals is performed separately, and the result of the operation is used as two inputs of a single-bias electro-optic modulator, and the spectrum of the single sideband modulated signal thus obtained is obtained. The two sidebands respectively carry the data of the two digital signals, thereby eliminating the need to separately modulate two digital signals by using a bipolar electro-optic modulator, which can save cost.

The various steps of the method of the second aspect may also refer to the respective operations of the respective modules and/or devices of the apparatus in the first aspect, and are not repeated here.

In a third aspect, an optical communication system is provided for processing a first digital signal and a second digital signal, the optical communication system including a transmitter, a receiver, and a connection at the transmitter and the receiving A fiber optic link between the machines, the transmitter includes a signal processing module, an arithmetic module, a digital to analog conversion module, and a single bias electro-optic modulator, the receiver including a photodiode, an amplifier, and a signal recovery module.

The signal processing module is configured to perform digital signal processing on the first digital signal to output a first real signal and a first imaginary signal, and perform digital signal processing on the second digital signal to output a second real signal and a second An imaginary signal, wherein frequencies of the first real signal and the first imaginary signal fall within an intermediate frequency X/2 portion of a bandwidth of the optical communication system, and frequencies of the second real signal and the second imaginary signal fall into the light a high frequency X/2 portion of the bandwidth of the communication system, wherein 1/2 ≤ X ≤ 2/3, the first imaginary signal is a Hilbert transform of the first real signal, and the second imaginary signal is the second a Hilbert transform of the real number signal; the operation module is configured to perform a first operation on the first real number signal and the second real number signal output by the signal processing module to obtain a first operation signal, and output the signal processing module Performing a second operation on the first imaginary signal and the second imaginary signal to obtain a second operation signal, wherein the first operation is an addition operation and the second operation is a subtraction operation, or the first operation is a subtraction operation And the second operation is an addition operation.

The digital-to-analog conversion module is configured to perform digital-to-analog conversion on the first operational signal to obtain a first analog signal, and perform digital-to-analog conversion on the second operational signal to obtain a second analog signal.

The single-bias electro-optic modulator is configured to receive the amplified signal of the first analog signal or the first analog signal, and the amplified signal of the second analog signal or the second analog signal, and perform electro-optic modulation to obtain a light domain a single sideband modulated signal, and the single sideband modulated signal is output to the optical fiber link via the single polarized light modulator, wherein the sidebands of the spectrum of the single sideband modulated signal respectively carry the first digital signal and the first Two-way digital signal data. The photodiode receives the single sideband modulated signal from the optical fiber link, and performs photoelectric conversion processing on the single sideband modulated signal to obtain a beat signal, wherein the intermediate frequency X/2 portion of the bandwidth of the beat signal carries the first The data of a digital signal, the high frequency X/2 portion of the bandwidth of the beat signal carries the data of the second digital signal, and the low frequency 1-X portion of the bandwidth of the beat signal serves as the beat interference of the signal and the signal SSBI's guard band. The amplifier is configured to perform amplification processing on the beat signal to obtain an amplified beat signal. The signal recovery module is configured to recover data of the first digital signal and the second digital signal from the amplified beat signal.

In conjunction with the third aspect, in an implementation of the third aspect, the optical communication system is a short-range optical communication system. In the field of optical communication, a short-range optical communication system refers to an optical communication system in which the total length of the above-mentioned optical fiber links is less than 80 km. Embodiments of the present invention are particularly applicable to short-range optical communication systems employing direct inspection techniques at the receiving end. In the embodiment of the present invention, the arithmetic operation of the real part and the imaginary part of the two digital signals is performed separately, and the result of the operation is used as two inputs of a single-bias electro-optic modulator, and the spectrum of the single sideband modulated signal thus obtained is obtained. The two sidebands respectively carry the data of the two digital signals, thereby eliminating the need to separately modulate two digital signals by using a bipolar electro-optic modulator, which can save cost.

On the other hand, the optical communication system of the embodiment of the present invention adopts direct inspection reception at the receiving end, and only requires one photodiode, and thus has a low cost. Moreover, after the end frequency beat, the SSBI falls within the guard band, reducing interference to the effective signal, so SSBI can be eliminated at the physical layer without digital processing, improving signal processing performance.

The module of the optical communication system of the third aspect can be implemented by referring to the corresponding module of the device of the first aspect. To avoid repetition, details are not described herein again.

DRAWINGS

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments or the prior art description will be briefly described below. Obviously, the drawings in the following description It is merely some embodiments of the present invention, and other drawings may be obtained from those skilled in the art without departing from the drawings.

1 is a schematic block diagram of an optical communication system in accordance with an embodiment of the present invention.

2 is an optical domain spectrum diagram of a dual polarization modulated output signal.

3 is an electric field spectrum diagram of a signal after photoelectric conversion of a dual polarization modulated output signal.

4 is a schematic block diagram of an apparatus for processing a signal in an optical communication system according to an embodiment of the present invention.

Figure 5 is a light domain spectrogram of an output signal in accordance with an embodiment of the present invention.

6 is another schematic block diagram of an apparatus for processing a signal in an optical communication system according to an embodiment of the present invention.

FIG. 7 is still another schematic block diagram of an apparatus for processing a signal in an optical communication system according to an embodiment of the present invention.

Figure 8 is a schematic block diagram of a receiver in accordance with an embodiment of the present invention.

9 is a schematic block diagram of an IQ modulator in accordance with an embodiment of the present invention.

Figure 10 is a schematic illustration of an output signal in accordance with an embodiment of the present invention.

11 is a schematic block diagram of a DD-MZM modulator in accordance with an embodiment of the present invention.

FIG. 12 is a schematic block diagram of a method of processing a signal in an optical communication system according to an embodiment of the present invention.

detailed description

The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is obvious that the described embodiments are a part of the embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of the present invention.

The technical solution of the present invention can be applied to various optical communication systems, for example, a Plesiochronous Digital Hierarchy ("PDH") optical communication system, and a Synchronous Digital Hierarchy ("SDH") optical communication system. Dense Wavelength Division Multiplexing (DWDM) optical communication system, all-optical optical communication system, and the like. The embodiment of the present invention mainly takes an application scenario as a short-distance wired optical communication system as an example for description. The short-distance optical communication system refers to an optical communication system in which the total length of the optical fiber is less than 80 km.

As shown in FIG. 1, a short-range wired optical communication system 100 applied to an embodiment of the present invention may include a transmitter 110, a fiber optic link 120, and a receiver 130. The transmitter 110 may include a signal processing circuit 111, a light source 112, and a modulator 113. The fiber link 120 may be composed of an optical fiber 121 and a repeater 122. The receiver 130 may include a photodiode 131, an amplifier 132, and a signal recovery unit 133. It should be noted that the signal processing circuit 111 may not be included in the system 100. In other words, the electrical input signal may be directly input to the modulator 113 to modulate the optical signal generated by the light source 112. In the optical communication system 100, the transmitter 110 is operative to convert an electrical input signal into an optical signal such that the optical signal can be transmitted over the fiber optic link 120. The receiver 130 is configured to receive the optical signal and convert the optical signal into an original electrical signal, that is, the electrical output signal of FIG. Additionally, in the system 100, the length of the optical fiber 121 is less than 80 km, and the receiver 130 employs a direct detection technique.

In the direct detection technology, in order to improve the spectral efficiency, one method is to map the two signals to be transmitted X1 and X2 to the frequency LF bandwidth part of the system 100 and the high frequency 1/1 at the transmitter 110 end. 3 digital two-way signals X3 and X4 of the bandwidth portion, or one digital signal to be transmitted is processed into the above two signals X1 and X2. As shown in FIG. 2, the two signals X3 and X4 are modulated by the modulator 113 on two orthogonal optical carriers, so that the SSBI can be made to fall at a low frequency of 1/3 protection at the receiver 130 end. In the frequency band, as shown in Figure 3. This can improve the spectrum efficiency from 1/2 to 2/3 while eliminating SSBI interference to the signal. In FIG. 3, B denotes a basic bandwidth, for example, B may be 50 GHz or 100 GHz, the sum of signals A1 and A2 is signal X3, and the sum of signals B1 and B2 is signal X4.

However, the above method requires the use of a bipolar electro-optic modulator, and the system cost is high. Embodiments of the present invention provide an apparatus for processing signals in an optical communication system, which solves the problem of high system cost in the above technology. A detailed description will be given below in conjunction with specific examples.

4 shows a schematic block diagram of an apparatus 200 for processing signals in an optical communication system in accordance with an embodiment of the present invention. The optical communication system is configured to transmit two digital signals, that is, a first digital signal X1 and a second digital signal X2, and the first digital signal X1 and the second digital signal X2 may be independent two digital signals. It can also be a two-way digital signal obtained by processing one digital signal. The present invention does not limit the specific processing of digital signals.

The apparatus 200 is an example of the transmitter 110 of FIG. 1 for processing the first digital signal X1 and the second digital signal X2. As shown in FIG. 4, the apparatus 200 includes a signal processing module 210, an arithmetic module 220, a digital to analog conversion module 230, and a single polarization electro-optic modulator 240.

In the embodiment of the present invention, the signal processing module 210, the operation module 220, and the device 200 The digital to analog conversion module 230 may be a specific example of the signal processing circuit 111 in the transmitter 110 of FIG. 1 for preprocessing the first digital signal X1 and the second digital signal X2 to output a desired The signal; the single-bias electro-optic modulator 240 in the device 200 may be a specific example of the modulator 113 in the transmitter 110 of FIG.

The signal processing module 210 is configured to perform digital signal processing on the first digital signal X1 to output a first real number signal I1 and a first imaginary number signal Q1, and perform digital signal processing on the second digital signal X2 to output a second real number signal. I2 and the second imaginary signal Q2.

In the embodiment of the present invention, the frequencies of the first real number signal I1 and the first imaginary number signal Q1 fall in the intermediate frequency X/2 portion of the bandwidth of the optical communication system, and the second real number signal I2 and the second imaginary number signal Q2 The frequency falls within the high frequency X/2 portion of the bandwidth of the optical communication system, where 1/2 ≤ X ≤ 2/3. In the embodiment of the present invention, the first imaginary signal QI is a Hilbert transform of the first real number signal I1, and the second imaginary number signal Q2 is a Hilbert transform of the second real number signal I2.

The operation module 220 is configured to perform a first operation on the first real number signal I1 and the second real number signal I2 outputted by the signal processing module 210 to obtain a first operation signal D1, and output the first imaginary number signal Q1 to the signal processing module. Performing a second operation with the second imaginary signal Q2 to obtain a second operational signal D2.

The first operation is an addition operation and the second operation is a subtraction operation, or the first operation is a subtraction operation and the second operation is an addition operation. That is, in the embodiment of the present invention, the operation module 220 is configured to add the two real signals I1 and I2 to obtain the first operation signal I1+I2, that is, D1=I1+I2, and perform the two imaginary signals Q1 and Q2. Subtracting, the second operational signal Q1-Q2 is obtained, that is, D2=Q1-Q2. Or the operation module 120 is configured to perform subtraction on the two real signals I1 and I2 to obtain the first operation signal I1-I2, that is, D1=I1-I2, and add the two imaginary signals Q1 and Q2 to obtain the second operation. Signal Q1 + Q2, that is, D2 = Q1 + Q2.

The digital-to-analog conversion module 230 is configured to perform digital-to-analog conversion on the first operational signal D1 to obtain a first analog signal Y1, and perform digital-to-analog conversion on the second operational signal D2 to obtain a second analog signal Y2.

The single-bias electro-optic modulator 240 is configured to receive the amplified signal of the first analog signal Y1 or the first analog signal Y1, and the amplified signal of the second analog signal Y2 or the second analog signal Y2, and perform electro-optic modulation to obtain The single sideband modulated signal Eout of the optical domain, wherein the sidebands of the spectrum of the single sideband modulated signal Eout respectively carry data of the first digital signal X1 and the second digital signal X2.

Optionally, in the embodiment of the present invention, X=2/3, wherein the first real number signal and the first virtual number The frequency of the number signal falls within the 1/3 portion of the IF of the bandwidth of the optical communication system, and the frequencies of the second real signal and the second imaginary signal fall into the high frequency 1/3 portion of the bandwidth of the optical communication system.

Optionally, in the embodiment of the present invention, as shown in FIG. 4, the single-polarization optical modulator 240 may include an optical input port EI, an optical output port EO, a first radio frequency port RF1, a second radio frequency port RF2, and a plurality of a DC bias port bias for inputting a continuous optical signal E1 for inputting an amplified signal of the first analog signal Y1 or the first analog signal Y1, the second RF port And an amplified signal for inputting the second analog signal Y2 or the second analog signal Y2, wherein the plurality of DC bias ports bias are used to respectively input a DC bias voltage.

In the embodiment of the present invention, the single-electron optical modulator 240 is configured to perform electro-optic modulation on the optical input port EI, the first RF port RF1, and the second RF port RF2 according to the DC bias voltage. A single sideband modulated signal Eout of the optical domain is obtained. The single sideband modulation signal Eout=Ein*(I1+Q1+I2-Q2) is output through the optical output port EO, and the two sidebands of the spectrum of the single sideband modulation signal Eout respectively carry the first digital signal The data of X1 and the second digital signal X2. As shown in FIG. 5, the output left band signal includes the signal I2-Q2, the output right band signal includes the signal I1+Q1, and the signal I1+Q1 carries the data of the first digital signal X1, and the signal I2-Q2 carries the second. The data of the digital signal X2.

In the embodiment of the present invention, the arithmetic operation of the real part and the imaginary part of the two digital signals is performed separately, and the result of the operation is used as two inputs of a single-bias electro-optic modulator, and the spectrum of the single sideband modulated signal thus obtained is obtained. The two sidebands respectively carry the data of the two digital signals, thereby eliminating the need to separately modulate two digital signals by using two single-bias electro-optic modulators, which can save cost.

The function of the signal processing module 210 in the embodiment of the present invention may be implemented by a DSP, or may be implemented by other chips or devices having a digital signal processing function. In addition, the operation module 220 in the embodiment of the present invention may be implemented by an adder and a subtractor, or may be implemented by a DSP. Similarly, the digital-to-analog conversion module 230 may be implemented by a digital-to-analog converter DAC or may have a digital-to-analog conversion. Functional DSP implementation. The specific implementation form of the operation module 220 and the digital-to-analog conversion module 230 is not limited in the embodiment of the present invention.

6 is a schematic diagram of an exemplary structure of an apparatus for processing a signal in an optical communication system according to an embodiment of the present invention. The DSP 211 and the DSP 212 in FIG. 6 may correspond to a specific implementation form of the signal processing module 210 in FIG. 4. The adder 221 and the subtractor 222 may correspond to a specific implementation form of the operation module 220 in FIG. The DAC 231 and the DAC 132 may correspond to a specific implementation form of the digital to analog conversion module 230 of FIG.

The DSP 211 in FIG. 6 can perform a series of processing on the first digital signal X1, such as serial-to-parallel conversion, Quadrature Amplitude Modulation (QAM) mapping, subcarrier mapping, ie, signal modulation, inverse Fourier. Inverse Fourier Transform ("IFFT"), increase cyclic prefix CP and parallel-to-serial conversion, etc.; DSP 212 in FIG. 6 can perform serial-to-parallel conversion, QAM mapping, subcarrier mapping, ie, signal on the second digital signal X2. Processing such as modulation, IFFT, adding CP, and parallel-to-serial conversion. In the embodiment of the present invention, the specific processing steps and sequence of the DSP 211 for the first digital signal X1 and the DSP 212 for the second digital signal X2 are not limited.

Specifically, the DSP 211 may output the first real number signal I1 and the first imaginary number by performing serial-to-parallel conversion, QAM mapping, sub-carrier mapping, ie, signal modulation, IFFT, increasing CP, and parallel-to-serial conversion on the first digital signal X1. Signal Q1, wherein the frequencies of I1 and Q1 fall within the 1/3 portion of the IF of the bandwidth of the optical communication system, and Q1 is the Hilbert transform of I1; likewise, DSP 212 can string the second digital signal X2 And converting, QAM mapping, subcarrier mapping, ie, signal modulation, IFFT, increasing CP, and parallel-to-serial conversion, and outputting the first real number signal I2 and the first imaginary number signal Q2, wherein the frequencies of I2 and Q2 fall into the optical communication system The high frequency 1/3 portion of the bandwidth, Q2 is the Hilbert transform of I2. The adder 221 can receive the first real number signal I1 and the second real number signal I2, add them to obtain the first operation signal I1+I2, and input the first operation signal I1+I2 to the DAC 231. The subtractor 222 can receive the first imaginary signal Q1 and the second imaginary signal Q2, subtract them to obtain the second operational signals Q1-Q2, and input the second operational signals Q1-Q2 to the DAC 232. The DAC 231 performs digital-to-analog conversion on the first operational signal I1+I2 to obtain a first analog signal Y1, and the DAC 232 performs digital-to-analog conversion on the second operational signal Q1-Q2 to obtain a first analog signal Y2. The first radio frequency port RF1 of the single-electron electro-optic modulator 240 receives Y1 or the amplified Y1, the second radio frequency port RF2 receives Y2 or the amplified Y2, and the optical input port EI of the single-bias electro-optic modulator 240 can be received by The continuous optical signal Ein generated by the laser 260 is a single-bias electro-optic modulator. The signal input from the optical input port Ein, the first RF port RF1, and the second RF port RF2 is electro-optically modulated by a DC bias voltage to obtain a single-sideband modulated signal Eout of the optical domain, where two spectra of Eout are obtained. The sidebands carry the data of X1 and X2, respectively, and Eout=Ein*(I1+Q1+I2-Q2).

In the embodiment of the present invention, as shown in FIG. 7, the output I1 and I2 can also be processed by the subtractor 222 to output the first operational signal I1-I2, and at the same time, Q1 and Q2 can be processed by the adder 221 to output the second. The operation signal Q1+Q2. At this time, I1-I2 is used as the input of the DAC 231, and undergoes digital-to-analog conversion. After the change, the first analog signal Y1, Q1+Q2 is obtained as the input of the DAC 232, and after the digital-to-analog conversion, the second analog signal Y2 is obtained.

In the embodiment of the present invention, I1+I2 can also be used as the input of the DAC 232. At this time, Q1-Q2 can be used as the input of the DAC 231. Similarly, I1-I2 can also be used as the input of the DAC 232. At this time, Q1+ Q2 can be used as an input of the DAC 231. The embodiment of the present invention does not limit the input of the DAC.

It should be understood that in the embodiment of the present invention, the DAC 231 and the DAC 232 may be the same DAC that can process at least two signals simultaneously, or may be different DACs. In the embodiment of the present invention, the DSP 211 and the DSP 212 may be the same DSP or different DSPs. The specific implementation form of the DSP is not limited in the embodiment of the present invention.

It should be understood that, in the embodiment of the present invention, the Ein is generated by the laser as an example. The source and specific form of the Ein are not limited in the embodiment of the present invention.

Optionally, in the embodiment of the present invention, the first digital signal X1 and the second digital signal X2 are PRBS digital signals.

Specifically, when X1 is PRBS1 and X2 is PRBS2, the input of DSP 211 is PRBS1, and the input of DSP 212 is PRBS1. In other words, the two signals to be processed by the device are PRBS1 and PRBS2.

Optionally, in the embodiment of the present invention, the modulation manner of the first real number signal I1, the first imaginary number signal Q1, the second real number signal I2, and the second imaginary number signal Q2 is direct multi-carrier technology DMT modulation or none The carrier amplitude phase is referred to as CAP modulation. It should be understood that the modulation method may also include other modulation methods.

It should be understood that, in the embodiment of the present invention, the QAM mapping is to implement frequency band compression of the signal, and the subcarrier mapping is to modulate the signal to implement spectrum shifting of the signal, specifically, processing the information of the signal to be loaded onto the subcarrier, so that It becomes a form suitable for channel transmission. The manner in which information can be carried during modulation includes: polarization direction, amplitude, frequency, phase, etc. These factors or a combination thereof are commonly referred to as modulation methods. The embodiment of the present invention is described by taking only the modulation mode including DMT modulation and CAP modulation as an example. The modulation mode is not limited in the embodiment of the present invention.

In the embodiment of the present invention, as shown in FIG. 8, the Eout is outputted through the optical output port, and is transmitted to the optical receiver 250 through one or more optical fibers. The optical receiver 250 can be implemented as shown in FIG. The optical receiver 130 may also be different from the implementation of the optical receiver 130. For example, the optical receiver 250 can include a photo diode ("PD"), an analog to digital converter ADC, a DSP, and the like. Specifically, as shown in FIG. 3 above, the Eout passes through one After the PD performs the beat frequency, the SSBI can fall within the low frequency 1/3 guard band. I1 can fall within the IF bandwidth of IF, and I2 can fall within the high frequency 1/3 bandwidth. In FIG. 3, the signal formed by the sum of the signal AI and the signal A2 is I1, and the signal formed by the sum of the signal BI and the signal B2 is I2. After the optical signal is converted into an analog electrical signal by the PD, the analog electrical signal is converted into a digital signal by an analog-to-digital converter (ADC), and finally a series of processing is performed on the digital signal by the DSP. The first digital signal X1 and the second digital signal X2 can be obtained by processing such as serial-to-parallel conversion, CP removal, Fourier transform FFT, subcarrier mapping, QAM mapping, and parallel-to-serial conversion.

It should be understood that the Eout is outputted through the optical output port, and then amplified by the reference fiber amplifier, and then transmitted. The embodiment of the present invention does not limit the transmission form. .

It should also be understood that the optical receiver 250 may further include an amplifying circuit, and the specific configuration of the optical receiver is not limited in the embodiment of the present invention.

Therefore, in the embodiment of the present invention, the arithmetic operation is performed on the real part and the imaginary part of the two digital signals, respectively, and the result of the operation is used as two inputs of a single-bias electro-optic modulator, thus obtaining the single sideband modulated signal. The two sidebands of the spectrum respectively carry the data of the two digital signals, thereby eliminating the need to separately modulate two digital signals by using a bipolar electro-optic modulator, which can save cost.

In addition, the above-described processing of the embodiment of the present invention is performed on two digital signals at the same time, and only one-third of the obtained low-sideband modulated signal is not used for transmitting data as a guard band for accommodating SSBI, so that it can be utilized. 2/3 of the spectrum resources achieve good system resource utilization while improving signal performance.

In the embodiment of the present invention, the single-polarization optical modulator 240 is an orthogonal IQ modulator, wherein the first RF port RF1 is an I port of the IQ modulator and the second RF port RF2 is the a Q port of the IQ modulator, or the first RF port RF1 is a Q port of the IQ modulator and the second RF port RF2 is an I port of the IQ modulator, the plurality of DC bias ports bias including the I a first bias port bias1 corresponding to the port, a second bias port bias2 corresponding to the Q port, and a third bias port bias3, wherein the DC bias of the first bias port bias1 is set at 0.75π, The DC bias voltage of the second bias port bias2 is set at 0.75π, and the DC bias voltage of the third bias port bias3 is set at 0.5π.

FIG. 9 shows a schematic block diagram of an IQ modulator 241 in accordance with an embodiment of the present invention. Specifically, in conjunction with FIG. 9, in the embodiment of the present invention, the carrier input Ein of the IQ modulator 241 passes through an optical coupler ("OC") OC1, and generates two signals with a power ratio of 1:1. , respectively, as inputs to the Intensity Modulator ("IM") IM1 and IM12. The input of the I port of IM1 is I1+I2, and the input of the Q port of IM2 is Q1-Q2. By adjusting the two DC bias voltages, both bias1 and bias2 are offset at 0.75π. For example, assuming that the half-wave voltage of the IQ modulator 241 is V _π = 4V, when the voltages input by both bias1 and bias2 are both 3V, both bias1 and bias2 are biased at 0.75π. At this time, the output of IM1 includes signal I1+I2 as shown in FIG. 10(a); the output of IM2 includes signals Q1-Q2 as shown in FIG. 10(b). By adjusting the DC bias voltage of the bias3 input, bias3 is biased at 0.5π, so that inside the IQ modulator 241, the output of IM2 passes through a phase shifter ("PS"), which produces 0.5π. The phase shift, the output of the PS includes the signal I1-I2, as shown in Figure 10(c). Thus, the two signals output through IM1 and PS pass through the OC2 output single sideband modulation Eout, as shown in FIG.

It should be noted that FIGS. 10(a), 10(b) and 10(c) and FIG. 5 only show that the output signal contains the labeled signal component, and is not a specific expression of the output signal. It should be understood that in the embodiment of the present invention, only I1+I2 is the input of the I port, and Q1-Q2 is the input of the Q port as a specific embodiment of the present invention. In the embodiment of the present invention, the input of the I port may also be I1-I2, and the input of the Q port may also be Q1+Q2. To avoid repetition, details are not described herein again.

In the embodiment of the present invention, the single-electrode optical modulator 240 is a parallel two-electrode Mach-Zehnder modulator DD-MZM, wherein the first RF port RF1 is an upper-arm RF input port of the DD-MZM and The second RF port RF2 is the DD-MZM lower arm RF input port, or the first RF port RF1 is the lower arm RF input port of the DD-MZM and the second RF port RF2 is the DD-MZM upper arm RF input a port, the plurality of DC bias ports bias includes a first bias port bias1 corresponding to the upper arm RF input port, and a second bias port bias2 corresponding to the lower arm RF input port, wherein the first bias The port is grounded, and the DC bias of the second bias port is set at 0.25π.

Specifically, in the embodiment of the present invention, as shown in FIG. 11, Ein is input as DD-MZM 242 as a continuous optical carrier signal, and Y1 and Y2 are used as two RF inputs of DD-MZM 242, respectively, through input RF1 and RF2, respectively. The two bias ports bias1 and bias2 of the DD-MZM are loaded with DC voltages V1 and V2, and one bias port is grounded, and the DC bias of the other bias port is set at 0.25π, which can obtain the optical domain. Single sideband modulated signal Eout.

It should be understood that since the working principle of the DD-MZM modulator is similar to that of the IQ modulator, in order to avoid repetition, no further details are provided herein.

It should also be understood that in the embodiment of the present invention, only the single-bias electro-optic modulator is an IQ modulator and The DD-MZM modulator is taken as an example for description. The specific form of the single-bias electro-optic modulator is not limited in the present invention.

Therefore, the apparatus for processing signals in the optical communication system according to the embodiment of the present invention performs arithmetic operations on the real part and the imaginary part of the two digital signals, respectively, and uses the calculated result as two inputs of a single-bias electro-optic modulator. The two sidebands of the spectrum of the single sideband modulated signal thus obtained respectively carry the data of the two digital signals, thereby eliminating the need to separately modulate two digital signals by using a bipolar electro-optic modulator, which can save cost.

The apparatus for processing signals in an optical communication system according to an embodiment of the present invention is described in detail above with reference to FIGS. 1 through 11, and a method of processing signals in an optical communication system according to an embodiment of the present invention will be described below with reference to FIG.

FIG. 12 shows a schematic flow diagram of a method 300 of processing signals in an optical communication system in accordance with an embodiment of the present invention. The optical communication system is configured to process a first digital signal and a second digital signal, wherein the first digital signal and the second digital signal are two digital signals transmitted by the optical communication system.

310. Perform digital signal processing on the first digital signal to output a first real number signal and a first imaginary number signal, and perform digital signal processing on the second digital signal to output a second real number signal and a second imaginary number signal, where The frequencies of the first real number signal and the first imaginary number signal fall within an intermediate frequency X/2 portion of the bandwidth of the optical communication system, and the frequencies of the second real number signal and the second imaginary number signal fall within the bandwidth of the optical communication system a high frequency X/2 portion, wherein 1/2 ≤ X ≤ 2/3, the first imaginary signal is a Hilbert transform of the first real signal, and the second imaginary signal is a hill of the second real signal Burt transform

320. Perform a first operation on the first real number signal and the second real number signal output by the signal processing module to obtain a first operation signal, and perform the first imaginary number signal and the second imaginary number signal output by the signal processing module. a second operation, where the second operation signal is obtained, wherein the first operation is an addition operation and the second operation is a subtraction operation, or the first operation is a subtraction operation and the second operation is an addition operation;

330, performing digital-to-analog conversion on the first operational signal to obtain a first analog signal, and performing digital-to-analog conversion on the second operational signal to obtain a second analog signal;

340. Perform single-sideband modulation by a single-bias electro-optic modulator, where the single-polarization optical modulator is configured to receive the first analog signal or an amplified signal of the first analog signal, and the second analog signal or the second analog Amplifying the signal and performing electro-optic modulation to obtain a single sideband modulated signal of the optical domain, and outputting the single sideband modulated signal to the optical fiber link via the single polarized optical modulator, wherein the single The sidebands of the spectrum of the sideband modulated signal respectively carry the data of the first digital signal and the second digital signal.

Embodiments of the present invention provide a method for processing a signal in an optical communication system, by performing arithmetic operations on real and imaginary parts of two digital signals, respectively, and using the calculated result as two paths of a single-bias electro-optic modulator. The input sidebands of the spectrum of the single sideband modulated signal thus obtained respectively carry the data of the two digital signals, thereby eliminating the need to separately modulate two digital signals by using a bipolar electro-optic modulator, which can save cost.

The steps of the method 300 may refer to the operations of the corresponding modules and/or devices of the apparatus 100 in FIG. 1 above. To avoid repetition, details are not described herein again.

It should be understood that the term "and/or" herein is merely an association relationship describing an associated object, indicating that there may be three relationships, for example, A and/or B, which may indicate that A exists separately, and A and B exist simultaneously. There are three cases of B alone. In addition, the character "/" in this article generally indicates that the contextual object is an "or" relationship.

It should be understood that, in various embodiments of the present invention, the size of the sequence numbers of the above processes does not mean the order of execution, and the order of execution of each process should be determined by its function and internal logic, and should not be directed to the embodiments of the present invention. The implementation process constitutes any limitation.

Those of ordinary skill in the art will appreciate that the elements and algorithm steps of the various examples described in connection with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both, for clarity of hardware and software. Interchangeability, the composition and steps of the various examples have been generally described in terms of function in the above description. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the solution. A person skilled in the art can use different methods for implementing the described functions for each particular application, but such implementation should not be considered to be beyond the scope of the present invention.

A person skilled in the art can clearly understand that, for the convenience and brevity of the description, the specific working process of the system, the device and the unit described above can refer to the corresponding process in the foregoing method embodiment, and details are not described herein again.

In the several embodiments provided by the present application, it should be understood that the disclosed systems, devices, and methods may be implemented in other manners. For example, the device embodiments described above are merely illustrative. For example, the division of the unit is only a logical function division. In actual implementation, there may be another division manner, for example, multiple units or components may be combined or Can be integrated into another system, or some features can be ignored or not executed. In addition, what is shown or discussed between each other The coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interface, device or unit, or an electrical, mechanical or other form of connection.

The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the objectives of the embodiments of the present invention.

In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above integrated unit can be implemented in the form of hardware or in the form of a software functional unit.

The integrated unit, if implemented in the form of a software functional unit and sold or used as a standalone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention contributes in essence or to the prior art, or all or part of the technical solution may be embodied in the form of a software product stored in a storage medium. A number of instructions are included to cause a computer device (which may be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods described in various embodiments of the present invention. The foregoing storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk, and the like. .

The above is only the specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and any equivalent person can be easily conceived within the technical scope of the present invention by any person skilled in the art. Modifications or substitutions are intended to be included within the scope of the invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims (14)

An apparatus for processing a signal in an optical communication system, wherein the optical communication system is configured to process a first digital signal and a second digital signal, the apparatus comprising: a signal processing module, configured to perform digital signal processing on the first digital signal to output a first real signal and a first imaginary signal, perform digital signal processing on the second digital signal to output a second real signal, and a second imaginary signal, wherein frequencies of the first real number signal and the first imaginary number signal fall within an intermediate frequency X/2 portion of a bandwidth of the optical communication system, the second real number signal and the second imaginary number signal The frequency falls within the high frequency X/2 portion of the bandwidth of the optical communication system, where 1/2 ≤ X ≤ 2/3, the first imaginary signal being a Hilbert transform of the first real signal, The second imaginary signal is a Hilbert transform of the second real signal; An operation module, configured to perform a first operation on the first real number signal and the second real number signal output by the signal processing module, to obtain a first operation signal, and output the first imaginary number to the signal processing module Performing a second operation on the signal and the second imaginary signal to obtain a second operation signal, wherein the first operation is an addition operation and the second operation is a subtraction operation, or the first operation is a subtraction operation and the The second operation is an addition operation; a digital-to-analog conversion module, configured to perform digital-to-analog conversion on the first operational signal to obtain a first analog signal, and perform digital-to-analog conversion on the second operational signal to obtain a second analog signal; a single-bias electro-optic modulator for receiving an amplified signal of the first analog signal or the first analog signal, and an amplified signal of the second analog signal or the second analog signal, and performing electro-optic modulation to obtain A single sideband modulated signal of the optical domain, wherein the sidebands of the spectrum of the single sideband modulated signal respectively carry data of the first digital signal and the second digital signal. The apparatus according to claim 1, wherein said X = 2/3, wherein a frequency of said first real number signal and said first imaginary number signal falls within an intermediate frequency of a bandwidth of said optical communication system In part 3, the frequencies of the second real number signal and the second imaginary number signal fall within a high frequency 1/3 portion of the bandwidth of the optical communication system. The apparatus according to claim 1 or 2, wherein the single-bias electro-optic modulator comprises an optical input port, a light output port, a first radio frequency port, a second radio frequency port, and a plurality of DC bias ports, The optical input port is configured to input a continuous optical signal, the first radio frequency port is configured to input the first analog signal or the amplified signal of the first analog signal, and the second radio frequency port is configured to input the second analog a signal or an amplified signal of the second analog signal, the plurality of DC bias ports are respectively for inputting a DC bias voltage, and the light output port is configured to output the single sideband tone Signal. The apparatus according to claim 3, wherein said single-polar electro-optic modulator is a quadrature IQ modulator, wherein said first radio frequency port is an I port of said IQ modulator and said second radio frequency The port is a Q port of the IQ modulator, or the first RF port is a Q port of the IQ modulator and the second RF port is an I port of the IQ modulator, the multiple DC offsets The voltage port includes a first bias port corresponding to the I port, a second bias port corresponding to the Q port, and a third bias port, wherein a DC bias setting of the first bias port At 0.75π, the DC bias of the second bias port is set at 0.75π, and the DC bias of the third bias port is set at 0.5π. The apparatus according to claim 3, wherein said single-bias electro-optic modulator is a parallel two-electrode Mach-Zehnder modulator DD-MZM, wherein said first RF port is an upper arm RF of said DD-MZM An input port and the second radio frequency port is the DD-MZM lower arm radio frequency input port, or the first radio frequency port is a lower arm radio frequency input port of the DD-MZM and the second radio frequency port is the a DD-MZM upper arm radio frequency input port, the plurality of DC bias ports including a first bias port corresponding to the upper arm radio frequency input port, and a second bias port corresponding to the lower arm radio frequency input port, wherein The first bias port is grounded, and the DC bias of the second bias port is set at 0.25π. The apparatus according to any one of claims 1 to 5, wherein the signal processing module, the arithmetic module and the digital to analog conversion module are implemented by a digital signal processor DSP. The apparatus according to any one of claims 1 to 6, wherein the first digital signal and the second digital signal are pseudo-random binary sequence PRBS digital signals. A method for processing a signal in an optical communication system, wherein the optical communication system is configured to process a first digital signal and a second digital signal, the method comprising: Performing digital signal processing on the first digital signal to output a first real signal and a first imaginary signal, and performing digital signal processing on the second digital signal to output a second real signal and a second imaginary signal, where a frequency of the first real number signal and the first imaginary number signal falls in an intermediate frequency X/2 portion of a bandwidth of the optical communication system, and frequencies of the second real number signal and the second imaginary number signal fall into the a high frequency X/2 portion of the bandwidth of the optical communication system, wherein 1/2 ≤ X ≤ 2/3, the first imaginary signal being a Hilbert transform of the first real signal, the second imaginary signal a Hilbert transform of the second real signal; The first real number signal and the second real number signal output by the signal processing module Performing a first operation to obtain a first operation signal, performing a second operation on the first imaginary signal and the second imaginary signal output by the signal processing module to obtain a second operation signal, where the first operation is Adding and the second operation is a subtraction operation, or the first operation is a subtraction operation and the second operation is an addition operation; Performing digital-to-analog conversion on the first operation signal to obtain a first analog signal, and performing digital-to-analog conversion on the second operation signal to obtain a second analog signal; Single sideband modulation by a single bias electro-optic modulator for receiving an amplified signal of the first analog signal or the first analog signal, and the second analog signal or Amplifying the signal of the second analog signal and performing electro-optic modulation to obtain a single sideband modulated signal of the optical domain, wherein the two sidebands of the spectrum of the single sideband modulated signal respectively carry the first digital signal and the second Road digital signal data. The method according to claim 8, wherein said X = 2/3, wherein a frequency of said first real number signal and said first imaginary number signal falls within an intermediate frequency of a bandwidth of said optical communication system In part 3, the frequencies of the second real number signal and the second imaginary number signal fall within a high frequency 1/3 portion of the bandwidth of the optical communication system. The method according to claim 8 or 9, wherein the single-bias electro-optic modulator comprises an optical input port, a light output port, a first radio frequency port, a second radio frequency port, and a plurality of DC bias ports, The optical input port is configured to input a continuous optical signal, the first radio frequency port is configured to input the first analog signal or the amplified signal of the first analog signal, and the second radio frequency port is configured to input the second analog a signal or an amplified signal of the second analog signal, the plurality of DC bias ports are used to respectively input a DC bias voltage, and the light output port is configured to output the single sideband modulated signal. The method of claim 10 wherein said single-polar electro-optic modulator is a quadrature IQ modulator, Wherein the first radio frequency port is an I port of the IQ modulator and the second radio frequency port is a Q port of the IQ modulator, or the first radio frequency port is a Q port of the IQ modulator And the second RF port is an I port of the IQ modulator, the multiple DC bias ports include a first bias port corresponding to the I port, and a second bias corresponding to the Q port a port, and a third bias port, wherein a DC bias of the first bias port is set at 0.75π, and a DC bias of the second bias port is set at 0.75π, the third bias port The DC bias is set at 0.5π. The method according to claim 10, wherein said single-bias electro-optic modulator is a parallel two-electrode Mach-Zehnder modulator DD-MZM, The first radio frequency port is an upper arm radio frequency input port of the DD-MZM and the second radio frequency port is the DD-MZM lower arm radio frequency input port, or the first radio frequency port is the DD- a lower arm radio frequency input port of the MZM and the second radio frequency port is the DD-MZM upper arm radio frequency input port, the plurality of DC bias ports including a first bias port corresponding to the upper arm radio frequency input port, and a second bias port corresponding to the lower arm radio frequency input port, wherein the first bias port is grounded, and a DC bias voltage of the second bias port is set at 0.25π. An optical communication system, characterized in that the optical communication system is configured to process a first digital signal and a second digital signal, the optical communication system comprising a transmitter, a receiver, and a transmitter and a receiver a fiber optic link between receivers, the transmitter comprising a signal processing module, an arithmetic module, a digital to analog conversion module, and a single bias electro-optic modulator, the receiver comprising a photodiode, an amplifier, and a signal recovery module, The signal processing module is configured to perform digital signal processing on the first digital signal to output a first real number signal and a first imaginary number signal, and perform digital signal processing on the second digital signal to output a second real number signal And a second imaginary signal, wherein frequencies of the first real signal and the first imaginary signal fall within an intermediate frequency X/2 portion of a bandwidth of the optical communication system, the second real signal and the second The frequency of the imaginary signal falls within the high frequency X/2 portion of the bandwidth of the optical communication system, where 1/2 ≤ X ≤ 2/3, and the first imaginary signal is Hilbert of the first real signal Transforming, the second imaginary signal is a Hilbert transform of the second real signal; The operation module is configured to perform a first operation on the first real number signal and the second real number signal output by the signal processing module to obtain a first operation signal, and output the first to the signal processing module Performing a second operation on the imaginary signal and the second imaginary signal to obtain a second operation signal, wherein the first operation is an addition operation and the second operation is a subtraction operation, or the first operation is a subtraction operation The second operation is an addition operation; The digital-to-analog conversion module is configured to perform digital-to-analog conversion on the first operational signal to obtain a first analog signal, and perform digital-to-analog conversion on the second operational signal to obtain a second analog signal; The single-bias electro-optic modulator is configured to receive an amplified signal of the first analog signal or the first analog signal, and an amplified signal of the second analog signal or the second analog signal, and perform electro-optic modulation Obtaining a single sideband modulated signal of the optical domain, and outputting the single sideband modulated signal to the optical fiber link via the single polarized optical modulator, wherein both sides of the spectrum of the single sideband modulated signal The data of the first digital signal and the second digital signal are respectively carried. The photodiode receives the single sideband modulated signal from the optical fiber link, and performs photoelectric conversion processing on the single sideband modulated signal to obtain a beat frequency signal, wherein an intermediate frequency of the bandwidth of the beat signal is X/ 2 partially carrying data of the first digital signal, the high frequency X/2 portion of the bandwidth of the beat signal carrying data of the second digital signal, and the low frequency 1-X of the bandwidth of the beat signal Part of the guard band of SSBI as part of the beat frequency of the signal and signal; The amplifier is configured to perform amplification processing on the beat signal to obtain an amplified beat signal; The signal recovery module is configured to recover data of the first digital signal and the second digital signal from the amplified beat signal. The optical communication system according to claim 13, wherein said optical communication system is a short-range optical communication system.

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