TWI235534B - Optical fiber loop laser module with adjustable wavelength and laser resonant cavity device thereof - Google Patents

Abstract

The present invention provides an optical fiber loop laser module with an adjustable wavelength and a laser resonant cavity device thereof. The optical fiber loop laser module includes an optic coupler, an optical filter, a Fabry-Perot laser diode with a multi-modal output, and an optical fiber amplification module, in which the optical fiber and the Fabry-Perot laser diode are located in a laser resonant cavity device. The output waves of a laser light produced and excited by the optical filter are injected into different modes of the Fabry-Perot laser diode. Meanwhile, the resonant properties of the Fabry-Perot laser diode are used to lock the output wavelength and power, thereby easily achieving the objectives of adjustable wavelength and stable output. Meanwhile, the present invention also has other advantages including simple structure, easy production, and low cost, etc.

Description

V. Description of the invention (1) [Technical field to which the invention belongs] In particular, the present invention relates to a loop laser module, an optical fiber loop laser module with a long adjustable and stable output [prior art]. Withered lasers are widely used in fiber-optic communications. In fiber-optic communications systems, most of the light sources used are

^ (Distributed feedback laser ^ DFB Dong r; r system: for optical communication, the distortion and energy attenuation of the optical signal will have a considerable impact on the stability of the system, the first stability. Long :: loop laser mainly Including-the laser cavity device and the two cavity device 10 as shown in the figure, which is an optical fiber, Fabry-Perot filter (Fiber Fabry-Perot ^^ '^^ scaring filter and polarization The controller oscillates, "糸 uses a fiber SFabry-Perot filter 12 to generate a specific laser" and passes through the polarization controller 14 to control the polarization of the laser in the loop by the polarization controller 丄 t. Polarization square Xiao 'means that different polarization controllers 14 are used to control the stable output of the optical fiber loop laser. However, the output wavelength and power of the laser cavity device 10 will still vibrate: Can not achieve the purpose of truly substantially stable output. Know another laser module technology with adjustable wavelength, such as US patent us 6373867, which uses polarization maintaining (Rolarizati one maintaining, PM) fiber and a saturation Absorber to produce a tunable ultrashort pulsed light The passive linear mode-locked resonant fiber laser is used to modulate the light source for long-distance optical transmission. However, in actual production, it is very important to explain the invention (2) It is difficult to make laser beams more expensive than ordinary optical fibers. In addition, the waveguide junction of the group is also changed for the purpose of mechanical metal vapor phase (MOVPE), so that the control and modification of the process can be adjusted and stabilized in view of this wavelength. [Abstract] The source of the invention is to simultaneously "Benefits" and further achieve the purpose of wavelength. The road laser module of the present invention and the cheap and cheap price of the road laser module of the present invention and the communication network as network data transmission. There is a modification such as the American crystal (Meta 1 output wavelength changes, so the main purpose of the optical fiber determined by the present invention has the advantages of different wavelengths at the same output and another laser co-existence. Another purpose is the laser co-light source The reliability is consistent with another purpose. Furthermore, the price of PM fiber is still higher than that of distance communication. Ordinary fiber is used as the laser-transformed semiconductor process to achieve the wavelength cut patent US 528479 1. With the formation of an organic vapor phase epitaxy, the switching 'causes the lack of costly semiconductor manufacturing. In view of the above problems, a loop laser module is proposed to effectively overcome the conventional knowledge and to provide a wavelength Switchable laser length selection and stable power output with dual output frequency range can be adjusted repeatedly as required. 'It is to provide a fiber-optic cavity resonator with a length of skin ^ m ^ m θ.' Simplified, production capacity is to provide a turbid total π a vibrating cavity device, which: ii :: the fiber optic reusable library for #, 1, directly applied to the optical communication monitoring network & On & A kind of I 1 wavelength tunable fiber back 1235534

Laser module, which can change the wavelength state through the change of temperature, and then achieve the effect of continuous mode selection output. μ shape

According to the present invention, a wavelength-tunable fiber-optic circuit laser module and a resonant cavity device are used as a laser resonance gain medium. An optical fiber amplification mode is output after gain amplification, and an optical coupler is used to make it Laser wave source output. The resonant cavity device includes a laser generator; a Fabry-Perot laser diode, which has multiple wheel-out modes and a fixed mode distance between each two output modes. In order to select one of the output modes according to different = lengths, and then convert the resonant wavelength laser into a wavelength-modulated laser corresponding to the output mode, meanwhile, use the Fabry-Perot laser diode. The characteristic locks the output wavelength of the laser. The following detailed description is provided through specific embodiments in conjunction with the accompanying drawings. It will be easier to understand the purpose, technical content, features and effects of the present invention. [Embodiment] The present invention uses a Fabry -Fabry-per 〇t laser diode and fiber-type Fabry-Perot (Fiber Fabry-Perot) filters are placed in the resonant cavity of the loop, in order to build a wavelength adjustable and stable doped铒 Fiber loop laser (Erbium-doped fiber r: ing laser), without the need to rely on the semiconductor process to achieve the purpose of wavelength switching. ^ As shown in the second figure, is a block diagram of the system architecture of the present invention, an optical fiber loop The laser module 20 includes a resonant cavity device 30, a fiber amplifier module 40, and a light coupler 50 in series to form an optical fiber circuit. Please also refer to the detailed structure diagram shown in the third figure. Using a resonant cavity device 30

V. Description of the invention (4) The structural design makes the output wavelength adjustable and stable. The resonant cavity device 30 includes a laser generator. The commonly used is a fiber Fabry_Perot filter 32 (Hereinafter referred to as FFp filter), which is placed in the resonant cavity device 30 to generate a wavelength; and a FabQ_Per ^ ot laser diode 34 (hereinafter referred to as a scared laser diode) Body), which has a heavy modal output, is a longitudinal model, and each output mode has a fixed mode distance, in order to select one of the modal outputs according to different wavelengths and then ^ within a wavelength range will The resonant wavelength injection generated by the FFP filter 32 is: = diode 34, and the Fp laser diode 34 converts the resonant wavelength into the main ', wavelength-modulated laser in the output mode, and The wavelength modulation is being performed. The laser diode 34 itself < M ° de spacing " is used to lock the selection and modulation; change ... each of the resonant wavelength lasers / long mode The modulation pitch is determined by the module pitch of the Fp laser diode 34. / 'The wavelength of the laser excited by the FFP filter 32 is matched with the wavelength-modulated laser of the polar body 34 of the requested laser 1; in addition, a piezoelectric conversion is provided in the skin device 32. (Ρζτ) to control the position of the central output wavelength of the FFP filter 32 by different Bulgaria voltages. Among them, the FP laser diode 34 is connected in series with an optical path circulator, and the laser diode 34 and the fiber amplifier module are connected in order to limit the wave two: change: the direction of the beam, and then make the beam Wrap around = limit

& At different temperatures, the mode separation of the FP laser diode 34 I: The temperature of the FP laser diode 34 is adjusted by using a thermostat to adjust the turn-off state of the wavelength, so that the output Wave == 1235534 V. Description of the invention (5) Continuation of the function of mode selection output. The optical fiber amplification module 40 is used as a wide-range light source output and laser gain output. It usually includes a pump laser source, a 980 nm pump laser 42 is commonly used, and a 1 480 / I550nm WDM optical coupler 44 is used. A series of Erbium-doped fiber (EDF) 46 'is connected in series to the aforementioned optical fiber circuit, which is used to excite Er ion through pump laser 42 to provide amplified excitation radiation (Amplified spontaneous emission). , ASE) source, the erbium-doped fiber 46 is connected to an optical unidirectional device 48 to fix the light source direction, and finally the laser wavelength is output through the optical coupler 44; among them, by adjusting the operating current of the pump laser 42, the The resonant wavelength laser is maintained at a constant power output. The invention injects the resonance wavelength generated by the FFP filter 32 into different output modes of the FD laser diode 34, so that the wavelength of the output laser can be modulated and the wavelength and power can be locked without being affected. The amount of polarization is disturbed; that is, the optical fiber loop laser module 20 of the present invention is limited by the number of Fp laser diodes 34, and the output and the optical fiber amplification module 40 bandwidth, so it can be different according to The wavelength range (use frequency band) of the device is required. Fp laser diodes 34 with different module distances are selected and placed in the optical fiber loop laser module 20 architecture to achieve wavelength modulation in different frequency bands. In understanding the structure of the present invention, one step illustrates that the present invention is particularly valuable in optical communication through a specific experimental framework. After the component package of the real road laser module 20 and its operation principle proposed by the present invention, in order to further the practical application and achieve the effect, the following shows the generality of the application and the latent architecture of the present invention as shown in Figure 4. The optical fiber contains an lx 2 and 10:90 optical coupling.

1235534 5. Description of the invention (6), device 50, FFP filter 32 in the resonant cavity, a FP laser diode 34 with multiple longitudinal modes and a mode distance of 1.12 nm, an optical path circulator 36, and an optical fiber Amplification module 40. The optical fiber amplification module 40 is composed of a 980 nm pump-laser laser 42, a 980/1 550 nm WDM coupler 44, a 12-meter doped pin: an optical fiber 46, and an optical unidirectional device 48. In addition, a measuring device 60 is connected to one of the coupling ends of the optical coupler 50 and includes a power meter 62 and an optical spectrum analyzer (OSA) 64 to measure the output power and the output spectrum, respectively. When the input current of the pump laser 42 is 180 mA, its output power is 100 mW; when the input current of the FP laser diode 34 is 15 mA, the center output wavelength is 1 533 · 84 nm. In addition, the FFP filter 32 has a relatively wide adjustable range, which has an insertion loss of less than 0.5 dB and a bias of about 0.1 dB.

Features include: Polarization-Dependent Loss (PDL), FSR of 44.5 nm, and Fineness of 200. In operation, a voltage (less than 12V) is applied to the piezoelectric converter (PZT) of the FFP filter 32 to control the wavelength output of the laser in the resonant cavity of the loop. To provide a stable operating frequency, the resonance wavelength filtered by the FFP filter 32 needs to match the wavelength of the FP laser diode 34 itself. Therefore, for a tunable wavelength-tunable laser (also called a multi-modal laser), the modulation spacing between the modes is through the multi-modality of the F p laser diode 34 The mode distance is determined by the mode distance. In this experimental example, the mode distance of the multi-mode laser is h 12 nm. In addition, when the base current is 15 mA, the side-mode output of the FP laser diode 34 will be well suppressed. The output spectrum and power are observed using a spectrum analyzer 64 and a power meter 42.

Page 11 1235534 V. Description of the invention (7) The biggest advantage of the fiber-optic loop laser architecture disclosed in the present invention is that the wavelength can be adjusted repeatedly within the same fixed output frequency range. The fifth (a) figure shows the spectrum graph output by the 'fiber-loop laser module 2 0' when the piezo converter of the FFP filter 32 is applied with different bias voltages. This wavelength can be adjusted in the range of 1528.28 nm. And 1559.64 nm. In general, the higher the side mode suppression ratio (Sidei〇de suppressi γ = \ ιο, SMSR), the better. The fifth (b) figure shows that when the modulation mode distance of the output wavelength is 1.12 nm, The relationship between the output power of the light wave, the SMSR ratio, and the laser wavelength. The results show that the maximum output power is 4 · i dBm, its wavelength appears at 1539 · 48 nm, and the SMSR values in the figure are all greater than 30 dB / 0 ·! Nm, and the output power is greater than 2 · 2 廿The modulation variable can reach 3m ·: (modulation range 1 528.28 nm ~ 1 559 · 64 nm). When the output light tone I is 1 535.00 nm, its SMSR will exceed 40.6 dB / 〇i nm (〇i ηΓ, which is the resolution of the spectrum analyzer). In short, when the optical fiber laser's input wavelength is fading from 1 528 · 28 nm to 1 559 · 6 4 nm and the mode interval is 1. 12 nm, the output light can be maintained at an SMSR greater than 30dB / 〇 ! ⑽, and the output power is maintained at greater than 2.2 dBm. In order to verify the stability of the output power and wavelength efficiency, the optical fiber loop laser module 20 and the traditional loop architecture are compared with each other. The FFP filter and a polarization controller are used in the laser. The comparison results are shown in the sixth figure. When the operating condition # 雷 & output wavelength is ⑽.86 nm, the power and frequency changes of the laser beam under the conditions of 900 seconds are observed. According to the observations shown in the sixth figure: the wavelength change and power fluctuation of the second road frame are respectively 0 nm and 0.22 dB; on the contrary

1235534 Five 'invention description (8) --- ground' The optical fiber loop laser module 20 proposed by the present invention can dynamically maintain the wheel wavelength variation of 0 nm (the reading rate of the instrument is 0 · nm) / and The variation of the optical output power is within 0.04 dB, and the longest output stability = holding time can exceed 4 hours. Therefore, the present invention can indeed make the output power and wave fluctuation small, so as to achieve the effect of adjustable wavelength and stable output.另外 In addition, by adjusting the operating electricity input to the 980 nm pump laser source, ^ keep the fiber-optic loop laser module 20 at a constant power output light g: it is displayed under the control of a fixed output power, 98nm laser Source: The relationship with the amount of operating current corresponding to the output light wave. When the output power of the optical fiber is set at 2.! DBm, and the power variation is less than + 〇 =:, the modulation range can reach 1 528.28 nm to 1 559 64⑽. The modulation range of L is between 1 3 5 m A to 175 m A. ', Therefore, it is different from the conventional polarization mode of the laser fiber in the conventional fiber control loop. The modal FP laser diode is selected and can provide an output wavelength and power phase source. The invention can change the output wavelength at the same fixed single input and output, can not only directly respond to the source, has a simple structure, and is easy to manufacture in an optical communication monitoring network. The output state of the wavelength is adjusted by using a 0-loop laser through a polarization controller. The present invention uses a mode with multiple time-locked output wavelengths, which can switch the laser and stable power output when the wavelength is stable. Therefore, within the output frequency range, it can be used repeatedly in optical communication networks as light and cheaply according to demand; it can improve the reliability of network data transmission in applications. When the temperature controller is used, the temperature can be changed to achieve continuous mode selection output.

1235534 V. Description of the invention (9)-The above descriptions explain the features of the present invention through examples. The purpose is to enable those skilled in the art to understand and implement the content of the present invention, rather than to limit the patent scope of the present invention. Therefore, all other equivalent modifications or modifications made without departing from the spirit disclosed in the present invention should still be included in the scope of patent application described below.

Page 14 1235534 Brief description of the drawings Description of the drawings The first picture is a conventional wavelength tunable picture. The structure block of Tian Shezhi's laser cavity. The second figure is the system of the present invention. The third figure is the detailed structure of the present invention. . The picture shows the present invention-specific experiment:,) The picture shows the FFp filter 1 of the present invention. Output spectrogram. Laser at U applied voltage The fifth (b) diagram is the output power and s diagram of the present invention. The ratio and the laser wavelength are shown in Fig. 6. The figure of the invention and the conventional structure about the change in power and frequency. Diagram. Description of power drawing number: 10 laser resonant cavity device 1 4 polarization controller 20 optical fiber loop laser module 30 resonant cavity device 34 FP laser diode 4 0 fiber amplifier module 44 WDM coupler 48 optical unidirectional device 60 Measuring device 12 FFP filter 32 FFP filter 3 6 Optical path circulator 4 2 Pump laser 4 6 Fiber-doped fiber 50 Optocoupler 62 Power meter Page 15 1235534 Schematic description 6 4 Spectrum analyzer

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Claims (1)

1235534 Look at the method ff — Fabry — Perot laser diode, which has multiple [pull out] states and every two of the output modes have a fixed mode distance, which can be selected according to different wavelength requirements of f An output mode, and further convert the resonant wavelength laser into a wavelength-modulated laser corresponding to the output mode within a wavelength f, and when performing wavelength modulation, use the Fabry-Perot The mode distance of the laser diode locks the output wavelength and power of the wavelength-modulated laser; an optical fiber amplifying module, which is used to capture the wavelength-modulated laser for gain and output; and A coupler is connected between the laser generator and the fiber amplifier module to modulate the laser with the wavelength after output gain. 2. The wavelength-tunable optical fiber loop laser module according to item 1 of the scope of the patent application, wherein the laser generator is an optical fiber Fabry-Perot filter, Let the laser system with the resonance wavelength be a filter. 3. The wavelength-tunable optical fiber loop laser module according to item 2 of the scope of the patent application, wherein the wavelength of the resonant wavelength laser filtered by the optical fiber Fabry-Perot filter is the same as that of the resonant wavelength laser. The wavelength modulated laser modulated by the Fabry-Perot laser diode matches. 4. The wavelength-tunable fiber-optic circuit laser module according to item 1 of the scope of patent application, wherein a piezoelectric converter is provided in the laser generator. 1235534 VI. Application for Patent Range (PZT) 'to control the original output wavelength of the resonant wavelength laser by different applied voltages. 5. The wavelength-tunable fiber-optic loop laser module according to item 1 of the scope of the patent application, wherein the modulation pitch of each wavelength mode of the resonant wavelength laser is the Fabry-Perot laser. The mode of the diode is determined. 6. The wavelength-tunable fiber-optic loop laser module according to item 1 of the scope of the patent application, further comprising an optical path circulator connected to the Fabry-Perot laser diode and the Between fiber amplifier modules. 7. The wavelength-adjustable fiber-optic loop laser module according to item 1 of the scope of patent application, further comprising a temperature controller to continuously adjust the temperature of the Fabry-Perot laser diode. These output modes are selected, and the wavelength achieves the effect of continuous mode selection output. Output 8. The wavelength-tunable fiber-optic loop laser module as described in item 丨 of the patent application scope, wherein the fiber amplifier module includes a light source, a device, an erbium-doped fiber, and an optical unidirectional device. Coupling 9. The wavelength profile as described in item 8 of the scope of the patent application, Gan + ^ n <You fiber loop laser module, where the light source is a pump laser. 10. The wavelength-tunable module according to item 8 of the scope of patent application, wherein the laser wavelength laser can be maintained at a constant power output by adjusting the operating current of the light source. ', Σ makes the resonance 11 · The wavelength-modulable module as described in item 丨 of the scope of the patent application', wherein '1¾ Fabry-Perot laser diode optical fiber loop laser. It is a multiple longitudinal mode. 1 2 · The wavelength-tunable fiber-optic circuit laser as described in the first item of the patent application scope. Ϊ235534 a'patent application range mode ,, ', and, by using the Fabry ~ polar body with different mode distances, the wavelength can be adjusted in different wavelength ranges to round the laser beam ^ — a kind of lightning A radiation cavity device, which is applied to-a wavelength-tunable loop laser module 'the fiber-optic circuit resonance cavity includes:-a laser generator' having at least one resonance cavity therein, and a laser with a mound wavelength; and 〃 A Fabry-Perot laser diode, which has multiple rotation modes, and there is a fixed distance between the two output modes to vary according to f Select one of the output modes, and then convert the resonant wavelength laser into a wavelength-modulated laser corresponding to the output mode in a wavelength range, and use this method when performing wavelength modulation. The mode distance of the Bupero laser diode locks the wavelength to modulate the output wavelength and power of the laser. 14. The laser cavity device according to item 13 of the scope of the patent application, wherein the laser generator is a fiber-type Fabry-Perot filter to generate the resonance. Wavelength lasers are filtered. 1 5 · The laser cavity device described in item 4 of the scope of the patent application, wherein the wavelength of the resonant wavelength laser filtered by the fiber-type Fabry-Perot filter is the same as that of the laser through the method. The wavelength modulated lasers modulated by the cloth black-perot laser diodes match. 16. The laser cavity device according to item 3 of the scope of the patent application, wherein the modulation pitch of each wavelength mode of the resonant wavelength laser is determined by the Fabry-Perot laser diode. Determined by the modulus. 1235534 'Scope of patent application 1 7 · The laser cavity device described in item 13 of the scope of patent application, one' further includes a temperature controller, which is used to adjust the Fabry-Perot laser I The temperature of the polar body continuously selects these output modes, so that the output wavelength can achieve the effect of continuous mode selection output. 18 · The laser cavity device according to item 13 of the scope of the patent application, wherein the Fabry-Perot laser diode system is a multiple longitudinal mode device. 19 · The laser ping-pong cavity device as described in item 13 of the scope of patent application, wherein the Fabry-Heart laser diode with the same mode distance is in different wavelength ranges Modulate the wavelength to rotate out.