CN103715598B - The cascade polarized main state high reliability alignment methods of semiconductor optical amplifier and system - Google Patents

Abstract

The invention discloses a semiconductor optical amplifier cascaded polarization main state high-reliability alignment method and system, wherein the method includes: taking two adjacent semiconductor optical amplifiers as a group, and adjusting the front-end semiconductor optical amplifier The front polarization controller makes the radius of the arc drawn by the output light polarization state of the front-end semiconductor optical amplifier on the Poincare sphere smaller until the arc is reduced to a point on the Poincare sphere; adjust the polarization state of the back-end semiconductor optical amplifier The front-end polarization controller makes the output light polarization state of the back-end semiconductor optical amplifier draw the radius of the arc on the Poincare sphere to become smaller until the arc is reduced to a point on the Poincare sphere; realize the polarization master of the semiconductor optical amplifier state alignment. The alignment method provided by the invention simplifies the operation of the demultiplexing system, reduces the cost, and has a very good role in promoting the development of the all-optical network and its polarization multiplexing technology.

Description

Semiconductor Optical Amplifier Cascaded Polarization Dominant State High Reliability Alignment Method and System

technical field

The present invention relates to the technical field of semiconductor optical amplifiers, in particular to a highly reliable alignment method and system for cascaded polarization main states of semiconductor optical amplifiers.

Background technique

At present, high-speed and large-capacity communication systems have become an inevitable trend, and polarization multiplexing is a development path. The polarization dominant states of semiconductor optical amplifiers are of great significance to the realization of optical polarization multiplexing technology.

When the polarization state of the input light is aligned with the polarization main state of the semiconductor optical amplifier, the polarization state of the output light of the semiconductor optical amplifier does not change with the change of the operating parameters such as the injection current of the semiconductor optical amplifier or the control optical power. On this basis, the polarization main state of the semiconductor optical amplifier is further adjusted to the pole of the Poincare sphere, so that the polarization state of the output light follows the change of the working parameters such as the injection current of the semiconductor optical amplifier, control optical power or signal optical power along the Poincar The change of the spherical equator can realize high-speed adjustment of the polarization state of the signal light.

Polarization multiplexing technology uses this characteristic of semiconductor optical amplifier to adjust and control the polarization state of signal light. Here, a key indicator is whether the polarization state of the input light can be rotated by 90 degrees. At present, a semiconductor optical amplifier usually cannot rotate the polarization state of the signal light by 90 degrees by changing the control optical power. In traditional polarization multiplexing, the linearly polarized light output by the laser is divided into two beams of orthogonally polarized light, and signal modulation is performed on them respectively. Two analyzers whose polarization analysis directions are perpendicular to each other are placed at the receiving end to detect two channels of signal light respectively. . This method requires that the direction of the polarizer must be consistent with the two polarization directions of the signal light at the transmitting end, and the communication optical path must use a polarization-maintaining fiber, which is expensive.

In addition, in order to meet the development requirements of the all-optical network, it is necessary to consider the cascading of multiple semiconductor optical amplifiers to realize the orthogonal rotation of the optically controlled signal light polarization state. When multiple semiconductor optical amplifiers work in cascade, the alignment of the main states of polarization of each semiconductor optical amplifier is the working basis for realizing the orthogonal rotation adjustment of the polarization state of signal light. However, the prior art does not involve the alignment method of the polarization principal state in the case of multiple semiconductor optical amplifiers being cascaded.

Contents of the invention

The object of the present invention is to provide a highly reliable method and system for aligning the main state of polarization in cascaded semiconductor optical amplifiers, which realizes the alignment of the main state of polarization in the case of cascading multiple semiconductor optical amplifiers.

The purpose of the present invention is achieved through the following technical solutions:

A high-reliability alignment method for cascaded polarization main states of semiconductor optical amplifiers, the method comprising:

Take two adjacent semiconductor optical amplifiers as a group, and adjust the pre-polarization controller of the front-end semiconductor optical amplifier, so that the output light polarization state of the front-end semiconductor optical amplifier draws a smaller radius on the Poincar sphere , until the arc shrinks to a point on the Poincar sphere;

Adjust the pre-polarization controller of the back-end semiconductor optical amplifier, so that the output light polarization state of the back-end semiconductor optical amplifier draws a smaller radius on the Poincare sphere until the arc is reduced to a point on the Poincare sphere ; Realize the alignment of the polarization main state of the semiconductor optical amplifier.

Further, the method also includes:

If the current cascaded semiconductor optical amplifier includes several groups of two adjacent semiconductor optical amplifiers, the alignment starts from a group of two adjacent semiconductor optical amplifiers close to the laser alignment light source until all semiconductor optical amplifiers are completed. Alignment of polarization principal states in optical amplifiers.

A semiconductor optical amplifier cascaded polarization main state high-reliability alignment system, the system includes:

Semiconductor optical amplifiers with pre-optical isolators, pre-polarization controllers and post-couplers are cascaded in series; each stage of semiconductor optical amplifiers is connected to the pre-optical optical The isolator is connected to a reverse laser;

Wherein, the input end of the cascade string is also connected with a laser for inputting and aiming at the light source.

Further, each semiconductor optical amplifier is also connected to a polarization state analyzer via a rear coupler.

Further, the system includes several groups of semiconductor optical amplifiers connected in series with a pre-laser, a pre-optical isolator, a pre-polarization controller and a post-coupler.

It can be seen from the above-mentioned technical solution provided by the present invention that the method for adjusting the main state of polarization of cascaded semiconductor optical amplifiers based on the principle of the main state realizes the alignment of the main state of polarization of the cascaded semiconductor optical amplifiers, thereby making the cascaded semiconductor optical amplifiers The change of the output polarization state caused by the change of the current or the control of the optical power changes around the aligned main state of polarization and rotates on the equator of the Poincar sphere. The changed polarization state is always a linear polarization state, thereby ensuring the minimum error in the direction of the magnetic field. Rotate the polarization state of the signal light by 90 degrees. Polarization multiplexing based on cascaded semiconductor optical amplifiers refers to transforming two independent control lights with signals into two orthogonal linear polarization states of one signal light by using the cross-polarization modulation effect of two-stage semiconductor optical amplifiers respectively. Above all, the receiving end only needs to detect the output of the polarization beam splitter to restore the original signal, thereby simplifying the operation of the demultiplexing system and reducing the cost. Realizing the polarization main state alignment of cascaded semiconductor optical amplifiers is of great significance for realizing the orthogonal rotation of the signal light optically controlled polarization state, thereby realizing dual-channel polarization multiplexing and improving the system capacity of the all-optical network. The development of its polarization multiplexing technology has a very good role in promoting.

Description of drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the accompanying drawings that need to be used in the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For Those of ordinary skill in the art can also obtain other drawings based on these drawings on the premise of not paying creative efforts.

FIG. 1 is a flow chart of a high-reliability alignment method for cascaded polarization master states of semiconductor optical amplifiers provided in Embodiment 1 of the present invention;

FIG. 2 is a schematic diagram of a semiconductor optical amplifier cascaded polarization main state high-reliability alignment system provided by Embodiment 2 of the present invention;

FIG. 3 is a schematic diagram of yet another semiconductor optical amplifier cascaded polarization main state high-reliability alignment system provided by Embodiment 2 of the present invention.

detailed description

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Embodiment one

FIG. 1 is a flow chart of a high-reliability alignment method for cascaded polarization master states of semiconductor optical amplifiers provided by Embodiment 1 of the present invention. As shown in Figure 1, the method mainly includes the following steps:

Step 11, take two adjacent semiconductor optical amplifiers as a group, and adjust the pre-polarization controller of the front-end semiconductor optical amplifier, so that the output light polarization state of the front-end semiconductor optical amplifier draws a circular arc on the Poincar sphere The radius gets smaller until the arc shrinks to a point on the Poincar sphere.

Specifically: first, adjust the control optical power of the front-end semiconductor optical amplifier, and observe the arc drawn by the polarization state of the output light on the Poincare sphere; then, adjust the front-end polarization controller of the front-end semiconductor optical amplifier to make the front-end semiconductor optical amplifier The radius of the circular arc drawn by the polarization state of the output light of the amplifier on the Poincare sphere becomes smaller; repeat the previous step, so that the radius of the circular arc drawn by the output light polarization state of the front-end semiconductor optical amplifier on the Poincare sphere becomes smaller and smaller , until the arc shrinks to a point on the Poincar sphere.

Step 12, adjust the pre-polarization controller of the back-end semiconductor optical amplifier, so that the output light polarization state of the back-end semiconductor optical amplifier draws a smaller radius on the Poincar sphere until the arc is reduced to be on the Poincar sphere A point of ; realize the alignment of the polarization main state of the semiconductor optical amplifier.

This step is similar to the specific implementation method of step 11, so it will not be repeated here. It needs to be emphasized that in the actual application process, if the current cascaded semiconductor optical amplifier contains several groups of two adjacent semiconductor optical amplifiers, then the group of two Each semiconductor optical amplifier starts to align until the alignment of the main states of polarization of all semiconductor optical amplifiers is completed.

The embodiment of the present invention is based on the main state principle of the cascaded semiconductor optical amplifier polarization main state adjustment method, which realizes the alignment of the semiconductor optical amplifier cascaded polarization main state, so that the current change of the cascaded semiconductor optical amplifier or the control optical power change causes The change of the output polarization state revolves around the aligned main state of polarization on the equator of the Poincar sphere, and the changed polarization state is always a linear polarization state, thereby ensuring the minimum error in the direction of the magnetic field, so that the polarization state of the signal light occurs 90 degree rotation. Polarization multiplexing based on cascaded semiconductor optical amplifiers refers to transforming two independent control lights with signals into two orthogonal linear polarization states of one signal light by using the cross-polarization modulation effect of two-stage semiconductor optical amplifiers respectively. Above all, the receiving end only needs to detect the output of the polarization beam splitter to restore the original signal, thereby simplifying the operation of the demultiplexing system and reducing the cost. Realizing the polarization main state alignment of cascaded semiconductor optical amplifiers is of great significance for realizing the orthogonal rotation of the signal light optically controlled polarization state, thereby realizing dual-channel polarization multiplexing and improving the system capacity of the all-optical network. The development of its polarization multiplexing technology has a very good role in promoting.

Embodiment two

An embodiment of the present invention provides a semiconductor optical amplifier cascaded polarization main state high-reliability alignment system, the system mainly includes:

Semiconductor optical amplifiers with pre-optical isolators, pre-polarization controllers and post-couplers are cascaded in series; each stage of semiconductor optical amplifiers is connected to the pre-optical optical The isolator is connected to a reverse laser;

Wherein, the input end of the cascade string is also connected with a laser for inputting and aiming at the light source.

Further, each semiconductor optical amplifier is also connected to a polarization state analyzer via a rear coupler.

Further, the system includes several groups of semiconductor optical amplifiers connected in series with a pre-laser, a pre-optical isolator, a pre-polarization controller and a post-coupler.

The schematic diagrams can be referred to accompanying drawings 2-3. FIG. 2 shows the alignment system of two semiconductor optical amplifiers cascaded polarization main states, and FIG. 3 shows the alignment system of several semiconductor optical amplifiers cascaded polarization main states.

In Figure 2-Figure 3, the illustrations are as follows: 1-laser, 2-optical isolator, 3-polarization controller, 4-semiconductor optical amplifier, 5-fiber coupler, 6-polarization analyzer, 7-laser , 8-optical isolator, 9-polarization controller, 10-semiconductor optical amplifier, 11-fiber coupler, 12-laser, 13-polarization analyzer.

In Fig. 2-Fig. 3, the laser 1 is connected in series with the optical isolator 2 through the optical fiber, the optical isolator 2 is connected in series with the polarization controller 3 through the optical fiber, the polarization controller 3 is connected in series with the semiconductor optical amplifier 4 through the optical fiber, and the semiconductor optical amplifier 4 is connected in series through the optical fiber The coupler 5 is connected in series with the optical isolator, polarization state analyzer 6 and laser 7 of the next stage respectively. After cascading multiple semiconductor optical amplifiers, each semiconductor optical amplifier has a polarization controller connected in series with it through an optical fiber. There is an optical isolator at the front end of the controller in series with it through an optical fiber, and the back end of the semiconductor optical amplifier is connected in series with the pre-optical isolator, polarization analyzer and laser of the semiconductor optical amplifier of the next stage through a fiber coupler. Finally, the optical The isolator 8 is connected in series with the polarization controller 9 through the optical fiber, the polarization controller 9 is connected in series with the semiconductor optical amplifier 10 through the optical fiber, and the semiconductor optical amplifier 10 is connected in series with the laser 12 and the polarization state analyzer 13 through the fiber coupler 11 respectively.

Wherein, the laser in the embodiment of the present invention can adopt the laser of the CQF935/708 model of JDS Uniphase Company, and the working band is at 1527-1610nm, which produces stable continuous light and control light; the semiconductor optical amplifier can adopt the IPSAD1501-5110 model of INPHENIX Company The semiconductor optical amplifier has a working current of 280mA, a maximum small signal gain of 23.6dB, and a polarization-dependent gain of 0.3dB; the polarization controller can be a manual polarization controller of the FPC561 model of THORLABS Company, the diameter of the fiber ring is 56mm, and the fiber ring can be adjusted The angle is plus or minus 117.5 degrees; or, use PHOTECH's PDL3309A motorized polarization controller, the driving voltage range is plus or minus 12V, and the wavelength range is 1250-1650nm, which is used to adjust and align the polarization main states of the two semiconductor optical amplifiers ; A polarization analyzer, THORLABS company PA530 polarization analyzer can be used to observe the polarization state of the output light on the Poincar sphere.

It should be noted that the specific implementation manners of the functions implemented by the various functional modules included in the above system have been described in detail in the previous embodiments, so details will not be repeated here.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person familiar with the technical field can easily conceive of changes or changes within the technical scope disclosed in the present invention. Replacement should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the protection scope of the claims.

Claims (5)

1. the cascade polarized main state high reliability alignment methods of semiconductor optical amplifier, it is characterised in that the method includes:

To the structure of Barebone it is: laser instrument is connected with optoisolator by optical fiber, optoisolator is connected with Polarization Controller by optical fiber, Polarization Controller is connected with semiconductor optical amplifier by optical fiber, semiconductor optical amplifier by fiber coupler respectively with the optoisolator of next stage, Polarization instrument and laser instrument series connection, cascade through multiple semiconductor optical amplifiers, there is a Polarization Controller each semiconductor optical amplifier front end by optical fiber series connection with it, there is an optoisolator Polarization Controller front end by optical fiber series connection with it, semiconductor optical amplifier rear end by fiber coupler respectively with the preposition optoisolator of the semiconductor optical amplifier of next stage, Polarization instrument and laser instrument series connection；

Using two the most adjacent semiconductor optical amplifiers as one group, and regulate the preposition Polarization Controller of front-end semiconductor image intensifer, the output polarization state making front-end semiconductor image intensifer draws the radius of circular arc in poincare sphere and diminishes, until the point that circular arc is reduced in poincare sphere；

The preposition Polarization Controller of regulation rear end semiconductor optical amplifier, the radius making the output polarization state of rear end semiconductor optical amplifier draw circular arc in poincare sphere diminishes, until the point that circular arc is reduced in poincare sphere；Realize the alignment of semiconductor optical amplifier principal state of polarization (psp).

Method the most according to claim 1, it is characterised in that the method also includes:

If in the semiconductor optical amplifier of current cascade, comprise two semiconductor optical amplifiers adjacent before and after some groups, then start alignment, until completing the alignment of all semiconductor optical amplifier principal state of polarization (psp) from two adjacent semiconductor optical amplifiers before and after a group of laser alignment light source.

3. the cascade polarized main state high reliability of semiconductor optical amplifier is to Barebone, it is characterised in that this system includes:

Semiconductor optical amplifier tandem with preposition optoisolator, preposition Polarization Controller and rearmounted bonder cascades；Every Level One semiconductor image intensifer is all via the preposition optoisolator of rearmounted bonder Yu rear stage semiconductor optical amplifier, and a return laser is connected；

Wherein, the input of this cascade string is also connected with one for inputting the laser instrument of alignment light source；

Its annexation is particularly as follows: laser instrument is connected with optoisolator by optical fiber, optoisolator is connected with Polarization Controller by optical fiber, Polarization Controller is connected with semiconductor optical amplifier by optical fiber, semiconductor optical amplifier by fiber coupler respectively with the optoisolator of next stage, Polarization instrument and laser instrument series connection, cascade through multiple semiconductor optical amplifiers, there is a Polarization Controller each semiconductor optical amplifier front end by optical fiber series connection with it, there is an optoisolator Polarization Controller front end by optical fiber series connection with it, semiconductor optical amplifier rear end by fiber coupler respectively with the preposition optoisolator of the semiconductor optical amplifier of next stage, Polarization instrument and laser instrument series connection.

System the most according to claim 3, it is characterised in that

Each semiconductor optical amplifier is also connected via rearmounted bonder and a Polarization instrument.

5. according to the system described in claim 3 or 4, it is characterised in that this system contains the some groups of semiconductor optical amplifier tandems with forward laser light device, preposition optoisolator, preposition Polarization Controller and rearmounted bonder and cascades.