WO2023035775A1 - 波长锁定器、可调激光器及波长锁定控制方法 - Google Patents

波长锁定器、可调激光器及波长锁定控制方法 Download PDF

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Publication number
WO2023035775A1
WO2023035775A1 PCT/CN2022/106287 CN2022106287W WO2023035775A1 WO 2023035775 A1 WO2023035775 A1 WO 2023035775A1 CN 2022106287 W CN2022106287 W CN 2022106287W WO 2023035775 A1 WO2023035775 A1 WO 2023035775A1
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wavelength
light source
tunable laser
source module
temperature
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PCT/CN2022/106287
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English (en)
French (fr)
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周换颖
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中兴光电子技术有限公司
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Publication of WO2023035775A1 publication Critical patent/WO2023035775A1/zh

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/02—Structural details or components not essential to laser action
    • H01S5/026—Monolithically integrated components, e.g. waveguides, monitoring photo-detectors, drivers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/06—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/06—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium
    • H01S5/062—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium by varying the potential of the electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/06—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium
    • H01S5/065—Mode locking; Mode suppression; Mode selection ; Self pulsating

Definitions

  • the present application relates to the technical field of optoelectronic devices, in particular to a wavelength locker, a tunable laser and a wavelength locking control method.
  • DWDM Dense Wavelength Division Multiplexing
  • a certain wavelength grid is predefined to monitor and calibrate the offset of the set channel, so as to adjust the driving of the laser for calibration.
  • reference etalons in optical communication systems mainly rely on free-space bulk materials, and are installed at the output end of tunable lasers, or as an independent package component, which limits the miniaturization of tunable lasers.
  • the integrated volume of the adjustable optical transmitter finally applied to the DWDM optical communication system.
  • embodiments of the present application provide a wavelength locker, a tunable laser, and a wavelength locking control method.
  • an embodiment of the present application provides a wavelength locker, which is applied to a tunable laser, and the tunable laser is provided with a light source module configured to emit a light beam with a required working wavelength
  • the wavelength locker includes: an optical input end , configured to connect to the light source module and receive light beams from the light source module, the light input end is also provided with a first connection end and a second connection end; the ring resonant cavity is connected to the second connection end,
  • the ring resonant cavity includes a ring waveguide winding, and a first beam splitter and a second beam splitter respectively connected to the ring waveguide winding, the ring waveguide winding, the first beam splitter and the The second beam splitter is configured to cooperate to generate a comb-shaped transmission spectrum;
  • the first photodetector, connected to the first connection end is configured to receive a part of the light emitted by the light source module to generate the first A photoelectric signal; a second photodetector, connected to the wavelength
  • an embodiment of the present application provides a tunable laser, including: the wavelength locker described in the first aspect; and a light source module configured to emit light beams, the optical input end is connected to the light source module A light beam with a desired working wavelength from the light source module.
  • an embodiment of the present application provides a wavelength locking control method, which is applied to a tunable laser, and the tunable laser includes the wavelength locker described in the first aspect;
  • the light source module of the light beam, the optical input end is connected to the light source module and receives the light beam from the light source module;
  • the control method includes: obtaining the first photoelectric signal output by the first photodetector and the first photoelectric signal output by the first photodetector The second photoelectric signal output by the second photodetector; obtain the wave-locking signal according to the first photoelectric signal and the second photoelectric signal; control the phase modulator to convert the wave-locking signal according to the wave-locking signal The working point is adjusted to the preset target position.
  • Fig. 1 is a schematic structural diagram of a wavelength locker provided by an embodiment of the present application
  • Fig. 2 is a schematic diagram of a transmission characteristic curve corresponding to an embodiment of the wavelength locker shown in Fig. 1;
  • FIG. 3 is a schematic structural diagram of a wavelength locker provided by another embodiment of the present application.
  • Fig. 4 is a schematic diagram of a transmission characteristic curve corresponding to an embodiment of the wavelength locker shown in Fig. 3;
  • Fig. 5 is a schematic structural diagram of a wavelength locker provided by another embodiment of the present application.
  • Fig. 6 is a schematic diagram of a transmission characteristic curve corresponding to an embodiment of the wavelength locker shown in Fig. 5;
  • FIG. 7 is a flowchart of a method for installing a wavelength locker provided in another embodiment of the present application.
  • Fig. 8 is a schematic diagram of a transmission characteristic curve corresponding to an embodiment of the wavelength locker shown in Fig. 7;
  • Fig. 9 is a schematic structural diagram of a tunable laser provided by an embodiment of the present application.
  • FIG. 10 is a flowchart of a wavelength locking method provided by an embodiment of the present application.
  • FIG. 11 is a flowchart of a specific implementation process of step S1020 in FIG. 10;
  • FIG. 12 is a flowchart of another specific implementation process of step S1030 in FIG. 10;
  • FIG. 13 is a flowchart of another specific implementation process of step S1032 in FIG. 12;
  • Fig. 14 is a schematic diagram of the effect of the wavelength locking method provided by an embodiment of the present application.
  • wavelength locker 100 wavelength locker 100, ring waveguide winding 110, first beam splitter 120, second beam splitter 130, optical input end 140, tunable laser 200, light source module 210, gain chip 211, external cavity filter device 212 , first photodetector 220 , second photodetector 221 , phase modulator 230 , temperature adjustment unit 240 , first temperature measurement unit 250 , and second temperature measurement unit 260 .
  • An embodiment of the present application provides a wavelength locker, a tunable laser, and a wavelength locking control method, wherein the optical input end can receive the light beam of the light source module, and the first beam splitter and the second beam splitter are respectively connected to the ring waveguide by winding wires , from the light beam from the light source module, a part of the light is output from the first connection end and received by the first photodetector to generate the first photoelectric signal; the other part of the light is output from the second connection end and enters the ring resonant cavity, and the filtered transmission The light is received by the second photodetector to generate a second photoelectric signal.
  • the wavelength shift of the tunable laser can be obtained to realize the function of wavelength monitoring; by controlling the phase modulator to adjust the working wavelength of the tunable laser at the preset target wavelength, the wavelength can be realized Locked function. Therefore, through the mutual cooperation of the optical input terminal, the ring resonant cavity, the first photodetector, the second photodetector and the phase modulator, it is possible to realize the The wavelength adjustment and monitoring function of the tunable laser can reduce the noise interference to the light source of the laser device, improve the adjustment accuracy, save the structural space of the wavelength locker, and reduce the complexity of the packaging process, thereby reducing the size of the tunable laser and reducing the cost.
  • Figure 1 is a schematic structural diagram of a wavelength locker 100 provided by an embodiment of the present application.
  • An embodiment of the present application provides a wavelength locker 100, which is applied to a tunable laser 200, and the tunable laser 200
  • a light source module 210 is provided, and the light source module 210 can emit light beams with required working wavelengths.
  • the wavelength locker 100 includes a ring resonant cavity, an optical input end 140 , a first photodetector 220 , a second photodetector 221 , and a phase modulator 230 .
  • the ring resonant cavity includes a ring waveguide winding 110 , and a first beam splitter 120 and a second beam splitter 130 respectively connected to the ring waveguide winding 110 .
  • the optical input end 140 can also be provided with a third connection end, the optical input end 140 is connected to the light source module 210 through the third connection end, receives part of the light beam emitted from the light source module 210, and is provided with a first connection end and a second connection end .
  • the first photodetector 220 is connected to the first connection end, receives part of the light emitted from the light source module 210, and generates a first photoelectric signal, while another part of light from the light source module 210 is output from the second connection end, and enters the ring resonant cavity , the filtered transmitted light is received by the second photodetector to generate a second photoelectric signal.
  • the first beam splitter 120 and the second beam splitter 130 are respectively connected to the ring waveguide winding 110, which can make the light beam enter the ring resonant cavity and transmit it resonantly, thereby realizing a comb with a free spectral range (Free Spectral Range, FSR) below 25 GHz
  • FSR Free Spectral Range
  • the shape transmission spectrum enables the wavelength locker 100 to achieve high-precision wavelength control and stabilization. Since the light beam in the wavelength locker 100 comes from the light beam emitted by the light source module 210 , that is, the light beam emitted by the tunable laser 200 , the light beam entering the wavelength locker 100 has the wavelength characteristics of the tunable laser 200 .
  • the first photodetector 220 and the second photodetector 221 respectively receive light of corresponding power from the light source module 210 to generate a first photoelectric signal and a second photoelectric signal respectively.
  • the working wavelength of the tunable laser 200 shifts, the first photoelectric signal and the second photoelectric signal change accordingly, so that the wavelength characteristics of the tunable laser 200 can be monitored.
  • the phase modulator 230 is arranged on the ring waveguide winding 110 in the wavelength locker 100, so that the temperature of the ring waveguide winding 110 can be adjusted by controlling the phase modulator 230, and the refractive index of the ring waveguide winding 110 can be changed, thereby changing the ring resonant cavity
  • the wavelength of the tunable laser 200 can be adjusted and locked by the wavelength locker 100 by adjusting the working point of the wave-locking signal to a preset target position.
  • the functions of laser wavelength locking and monitoring can also be realized by using external F-P etalons, gratings, filter arrays, etc., but due to their large size, complex control systems are required, and there are large reflections.
  • the wavelength locker 100 can integrate the optical input terminal 140, the ring resonant cavity, the first photodetector 220, the second photodetector 221 and the phase modulator 230 on the SOI chip, without the need for an external body-type F-P etalon, Large-scale components such as gratings and filter arrays can realize the wavelength monitoring, adjustment and locking functions of the tunable laser 200, reduce the noise interference generated by the light source of the laser device, improve the adjustment accuracy, and save the structure of the wavelength locker 100 The space can reduce the size of the product, and at the same time reduce the complexity of the packaging process and reduce the cost.
  • first beam splitter 120 and the second beam splitter 130 may be directional couplers or multimode interferometers
  • the ring waveguide winding 110 may be a silicon nitride waveguide winding, that is, a SiN waveguide
  • the winding can also be a deep-etched silicon waveguide winding, which can adopt different waveguide windings or adjust the splitting ratio of the beam splitter according to different usage scenarios.
  • the wavelength locker 100 is also provided with a first temperature measurement unit 250, the first temperature measurement unit 250 is located in the wavelength locker 100, wherein the wavelength locker 100 is also provided with metal electrodes, and the metal electrodes are used for mounting and fixing
  • the first temperature measuring unit 250, and the metal electrode can be located inside or outside the ring resonant cavity. Therefore, the first temperature measurement unit 250 is integrated and mounted on the chip of the wavelength locker 100, the first temperature data of the wavelength locker 100 is obtained, and the temperature change of the wavelength locker 100 can be monitored in real time, thereby accurately controlling the tunable laser 200
  • the stable wavelength is beneficial to realize the wavelength monitoring and locking function of the wavelength locker 100, and can reduce the packaging volume of the tunable laser 200 and reduce the cost.
  • the tunable laser 200 is further provided with a temperature adjustment unit 240 configured to control the temperature of the tunable laser 200 and the temperature of the wavelength locker 100 at the same time.
  • the light source module 210 of the tunable laser 200 is further provided with a second temperature measurement unit 260 configured to monitor temperature changes in the light source module 210 . Therefore, when the temperature adjustment unit 240 adjusts the temperature of the tunable laser 200, and the first temperature measurement unit 250 and the second temperature measurement unit 260 monitor the temperature changes of the wavelength locker 100 and the light source module 210 respectively, the tunable laser 200 can be monitored.
  • the wavelength changes, and the wavelength control and stabilization are coordinated to realize the wavelength locking function.
  • the wavelength locker 100 and the tunable laser 200 may be integrated on the same silicon-based chip, that is, an SOI (Silicon-on-Insulator, SOI) chip.
  • SOI Silicon-on-Insulator
  • the external reference standard is bulky and needs to be installed at the output of the tunable laser 200, but due to the size mismatch between the off-chip reference etalon-based wavelength locking component and the tunable laser 200, a mixed Integration, or independent control and placement of the reference etalon, which increases the complexity of the control system and packaging process, reduces reliability, and increases costs.
  • the wavelength locker 100 and the tunable laser 200 are integrated on the same SOI chip, there is no need to separately package optical elements, the size of the product can be reduced, the complexity of the packaging process can be reduced, and the independent packaging of the wavelength locker 100 can be avoided to reduce wavelength locking.
  • the reliability of the mechanical vibration of the device 100 and the sensitivity of temperature improve the adjustment accuracy and stability.
  • the wavelength locker 100 and the tunable laser 200 are integrated on the same SOI chip, there is no need to place the wavelength locker 100 at the output end of the tunable laser 200, which reduces the impact of the wavelength locker 100 on external optical feedback and improves Stability of wavelength locker 100 .
  • FIG. 2 is a schematic diagram of a corresponding transmission characteristic curve provided by an embodiment of the wavelength locker 100 shown in FIG. 1.
  • the PD2 curve shown in FIG. and the shown PD3 curve, that is, the solid line, is the transmission characteristic curve of the second photodetector 221 .
  • the ring waveguide winding 110 can receive the light beam emitted by the light source module 210 through the optical input end 140.
  • the optical input end 140 can be composed of a first reflector and a beam splitting element.
  • the first reflector and The beam-splitting element is coupled, that is, the first reflector cooperates with the beam-splitting element to realize optical coupling and splitting, and the first reflector and the beam-splitting element split the optical power of the same wavelength, wherein the beam-splitting element can be directional The coupler, so that the light received by the light input end 140 can be split by the first reflector, and the beam splitting element can receive part of the light split by the first reflector.
  • the directional coupler can be set with a splitting ratio of 85:15 at a wavelength of 1550 meters, and the optical input end 140 is respectively provided with a first connection end and a second connection end. Therefore, the first connection end and the second connection end are respectively 15% of the light beam is emitted, and the first connection end is connected with the first photodetector 220, and the second connection end is connected with the ring resonant cavity, and the light splitting ratio between the first connection end and the second connection end can be set at a wavelength of 1550nm as 40:60.
  • the first photodetector 220 40% of the light beam emitted from the first connection end is received by the first photodetector 220, and 60% of the light beam emitted from the second connection end enters the ring resonator to form a resonant light beam, while the through-hole in the first beam splitter 120
  • the terminal is connected with the second photodetector 221 to receive the periodic resonant transmitted light.
  • the beam splitting ratio of the first beam splitter 120 and the second beam splitter 130 is the same, set to 0.75, therefore, 25% of the resonant beams of the beams entering the first beam splitter 120 enter the second photodetector 221, thus, At a wavelength of 1550nm, the ratio of the input optical power of the first photodetector 220 to the input optical power of the second photodetector is 8:3, and the transmission performance data of the wavelength locker 100 is obtained, which is convenient for subsequent wavelength adjustment and improvement. Stability and reliability of the wavelength locker 100.
  • the FSR of the wavelength locker 100 can be set to 25 GHz
  • the first mirror is a deep etched silicon waveguide element
  • the ring resonator includes a ring waveguide winding 110, the first beam splitter 120 and the second beam splitter 130, which are made of nitrogen Silicon nitride waveguide components
  • the height of the silicon nitride waveguide is 400nm
  • the typical width is 1 ⁇ m
  • the width of the waveguide winding is 2 ⁇ m
  • the length of the tapered waveguide from 1 ⁇ m to 2 ⁇ m is 40 ⁇ m
  • the group refractive index of the silicon nitride waveguide is 1.985
  • the waveguide winding The length of the line can be calculated by the following waveguide length relation:
  • L is the length of the waveguide winding
  • ⁇ is the wavelength
  • FSR is the free spectrum range
  • n g is the group refractive index.
  • the length corresponding to the waveguide winding of the wavelength locker 100 at an FSR of 25 GHz is 6063.5 ⁇ m.
  • the transmission characteristic curve corresponding to the first photodetector 220 is a straight line of 0.4
  • the transmission characteristic curve corresponding to the second photodetector 221 is a periodic comb curve between 0.35 and 0.6, so
  • the second photoelectric signal generated by the second photodetector 221 can be processed by the ratio of the first photoelectric signal generated by the first photodetector 220 to obtain a wave-locked signal, and the obtained wave-locked signal is also a periodic comb curve, which can realize 25GHz Therefore, the precision requirement of the wavelength control of the tunable laser 200 can be met.
  • the wavelength locker 100 can adjust the length of the waveguide winding to adjust the required FSR according to the group refractive index of the waveguide winding and the required beam wavelength, or can adjust the required FSR according to the group refractive index of the waveguide winding and the required beam wavelength, Adjust the FSR to adjust the length of the waveguide winding.
  • the structural design of the wavelength locker 100 is flexible, and the length and winding mode of the waveguide can be adjusted to save structural space, reduce the size of the product, and can also adjust the FSR, which is suitable for different usage scenarios and improves the adjustment accuracy and wavelength stability.
  • Figure 3 is a schematic structural view of a wavelength locker 100 provided by another embodiment of the present application
  • Figure 4 is an embodiment of the wavelength locker 100 shown in Figure 3 providing corresponding transmission characteristics
  • the schematic diagram of the curve, the PD2 curve shown in FIG. 4 namely the dotted line, is the transmission characteristic curve of the first photodetector 220
  • the optical input end 140 can be formed by coupling the second reflector and the third reflector, that is, a directional coupler can be formed between the second reflector and the third reflector, and the optical power of the same wavelength can be shunted.
  • Both the second reflector and the third reflector are annular reflectors.
  • the light received by the light input end 140 can be divided by the second reflector, and the third reflector can receive the light received by the second reflector. part of the light and transmit it.
  • the optical input end 140 can be composed of different optical elements, so that different types of optical input end 140 can be selected according to different usage scenarios, and the structural design is flexible and adaptable, and The number of components used is small, the volume is small, the production complexity is reduced, and the product size is reduced.
  • the second reflector and the third reflector are connected through a first directional coupler, and the splitting ratio is 90:10, that is, the second reflector couples 10% of the light beams output from the light source module 210 to the third reflector.
  • a first port is set on the third reflector, and it is set to output part of the light in the third reflector, and a second directional coupling with a light splitting ratio of 80:20 is provided between the first port and the ring resonant cavity
  • the second directional coupler is provided with a second port and a third port, the second port is connected with the first photodetector 220, receives 20% of the light beam from the first port light beam, and the third port is connected with the ring resonant cavity , receiving 80% of the beams from the first port.
  • the beam splitting ratio of the first beam splitter 120 and the second beam splitter 130 can be set to be the same, and the beam splitting ratio is set to 25:75, therefore, 25% of the beams entering the ring resonator can enter the second photodetector 221, therefore, at a wavelength of 1550nm, the ratio of the input optical power of the first photodetector 220 to the input optical power of the second photodetector 221 is 1:1, thus, according to the required performance data of the wavelength locker 100 , adjust the components of the optical input end 140, or adjust the light splitting ratio of the first beam splitter 120, so as to facilitate subsequent wavelength adjustment and improve the sensitivity and stability of the wavelength locker 100.
  • the FSR of the wavelength locker 100 can be set to 25 GHz
  • the second mirror is a deep etched silicon waveguide element
  • the ring resonator includes a ring waveguide winding 110, the first beam splitter 120 and the second beam splitter 130, which are made of nitrogen Silicon nitride waveguide components
  • the height of the silicon nitride waveguide is 400nm
  • the typical width is 1 ⁇ m
  • the width of the waveguide winding is 2 ⁇ m
  • the length of the tapered waveguide from 1 ⁇ m to 2 ⁇ m is 40 ⁇ m
  • the group refractive index of the silicon nitride waveguide winding is 1.985
  • the length of the wave winding can be calculated by the waveguide length relational formula in the above embodiment, and the length corresponding to the waveguide winding of the wavelength locker 100 with an FSR length of 25 GHz is 6063.5 ⁇ m.
  • the transmission characteristic curve corresponding to the first photodetector 220 is a straight line of 0.2
  • the transmission characteristic curve corresponding to the second photodetector 221 is a periodic comb curve between 0.5 and 0.8, so Ratio processing the second photoelectric signal generated by the second photodetector 221 and the first photoelectric signal generated by the first photodetector 220 to obtain a wave-locking signal, which is also a periodic comb-shaped curve, and can achieve wavelengths below 25 GHz interval, so that the precision requirement of the wavelength control of the tunable laser 200 can be met.
  • the wavelength locker 100 can achieve a wavelength accuracy of 25 GHz.
  • the wavelength locker 100 can select the type of the optical input end 140 according to the actual situation, adjust the splitting ratio of the optical input end 140 or adjust the splitting ratio of the first beam splitter 120, the structure design is flexible, the volume is small, and the adjustment accuracy and wavelength stability can be improved. sex.
  • Figure 5 is a schematic structural view of a wavelength locker 100 provided by another embodiment of the present application
  • Figure 6 is an embodiment of the wavelength locker 100 shown in Figure 5 providing corresponding transmission characteristics
  • the schematic diagram of the curve, the PD2 curve shown in FIG. 6 namely the dotted line, is the transmission characteristic curve of the first photodetector 220
  • the light input end 140 may be a fourth mirror, which is provided with a third directional coupler and a fourth port, and is configured to output part of the light split from the light source module 210 of the tunable laser 200 .
  • the optical input end 140 can only use the fourth reflector, and the ring waveguide winding 110 can receive the light beam from the light source module 210 through the fourth reflector, which has a simple structure, saves space, and can reduce product size and production capacity. difficulty.
  • the optical input end 140 adopts the fourth reflector, and by adjusting the splitting ratio of the fourth reflector, the performance data of the wavelength locker 100 can be adjusted, and a high-precision adjustment function can be realized while maintaining the advantage of small size.
  • the third directional coupler on the fourth mirror has a splitting ratio of 25:75 at a wavelength of 1550nm, so 25% of the light beam exits the fourth port and enters the fourth orientation with a splitting ratio of 75:25 coupler, a first connection end and a second connection end are arranged on the fourth directional coupler; that is, for the light emitted from the fourth port, 25% of the light beam output from the first connection end is received by the first photodetector 220, and there is 75% of the light beam is output from the second connection end and enters the ring resonant cavity to form a resonant light beam.
  • the light splitting ratios of the first beam splitter 120 and the second beam splitter 130 in the ring resonator are both 25:75, that is, the second photodetector 221 can receive 25% of the light beam from the second connection end. Therefore, at a wavelength of 1550 nm, the ratio of the input optical power of the first photodetector 220 to the input optical power of the second photodetector 221 is 4:3.
  • the optical input end 140 composed of different components, the ratio of the input optical power of the first connection end to the input optical power of the second connection end can be adjusted, the structural design is flexible, and different types of optical input end 140 can be selected according to actual needs, reducing the process complexity, and improve the sensitivity and stability of the wavelength locker 100.
  • the transmission characteristic curve corresponding to the first photodetector 220 is a straight line of 0.25
  • the transmission characteristic curve corresponding to the second photodetector 221 is a periodic comb curve between 0.4 and 0.7
  • the second photoelectric signal generated by the second photodetector 221 is compared with the first photoelectric signal generated by the first photodetector 220 to obtain a wave-locking signal, and the obtained wave-locking signal is also a periodic comb curve, which can realize 25GHz Therefore, the precision requirement of the wavelength control of the tunable laser 200 can be met.
  • the ring resonator when the fourth mirror is a deep etched silicon waveguide element, the ring resonator includes a ring waveguide winding 110, a first beam splitter 120 and a second beam splitter 130, which are silicon nitride waveguide elements, and the height of the silicon nitride waveguide is 400nm, the typical width is 1 ⁇ m, the width of the waveguide winding is 2 ⁇ m, the length of the tapered waveguide from 1 ⁇ m to 2 ⁇ m is 40 ⁇ m, the group refractive index of the silicon nitride waveguide winding is 1.985, and the length of the waveguide winding is set to 6063.5 ⁇ m, which can realize 25GHz FSR. Therefore, the wavelength locker 100 has a flexible and simple structural design, a small volume, can realize high-precision wavelength control, and improves stability and reliability.
  • Figure 7 is a schematic structural diagram of a wavelength locker 100 provided by another embodiment of the present application
  • Figure 8 is an embodiment of the wavelength locker 100 shown in Figure 5 providing corresponding transmission characteristics
  • the optical input end 140 can be a coupled first reflector and a beam splitting element, that is, the first reflector and the beam splitting element cooperate to realize optical coupling and splitting, and the first reflector and the beam splitting element have an optical power of the same wavelength Splitting, wherein the beam splitting element can be a directional coupler, so that the light received by the optical input end 140 can be split by the first reflector, and the beam splitting element can receive the light split by the first reflector Part of the light is transmitted, wherein the first reflector is a deeply etched silicon waveguide element, and the waveguide winding is a deeply etched silicon waveguide element.
  • the optical input end 140 can be composed of different components, or the material of different component components can be replaced, so as to be applicable to different usage scenarios, reduce product size, and improve stability and reliability.
  • the directional coupler can be set with a splitting ratio of 85:15 at a wavelength of 1550 meters, and the optical input end 140 is respectively provided with a first connection end and a second connection end, and the first connection end is connected to the first photodetector 220 , the second connection end is connected to the ring resonant cavity, and the light splitting ratio between the first connection end and the second connection end can be set to 40:60 at a wavelength of 1550 nm.
  • the first photodetector 220 40% of the light beam emitted from the first connection end is received by the first photodetector 220, and 60% of the light beam emitted from the second connection end enters the ring resonator to form a resonant light beam, while the through-hole in the first beam splitter 120
  • the terminal is connected with the second photodetector 221 to receive the periodic resonant transmitted light.
  • the beam splitting ratio of the first beam splitter 120 and the second beam splitter 130 is the same, set to 0.75, therefore, 25% of the resonant beams of the beams entering the first beam splitter 120 enter the second photodetector 221, thus, At a wavelength of 1550nm, the ratio of the input optical power of the first photodetector 220 to the input optical power of the second photodetector 221 is 8:3. It can be seen from FIG. 8 that the transmission corresponding to the first photodetector 220 The characteristic curve is a straight line of 0.4, and the transmission characteristic curve corresponding to the second photodetector 221 is a periodic comb-shaped curve between 0.35 and 0.6.
  • the same optical splitter is set by using the same components to form the light input end 140.
  • changing waveguide windings of different materials and mirrors of different materials will not affect the performance of the wavelength locker 100, therefore, it has high stability and high reliability.
  • the first reflector is a deeply etched silicon waveguide element
  • the ring resonator includes a ring waveguide winding 110
  • the first beam splitter 120 and the second beam splitter 130 are deeply etched silicon elements
  • the height of the silicon waveguide is 220nm
  • deep The eclipse thickness is 90nm
  • the waveguide width is 500nm
  • the group refractive index is 3.894.
  • the free spectrum range is set to 25GHz
  • the length of the waveguide winding is 3084.87 ⁇ m. Therefore, by changing the material of the components constituting the wavelength locker 100 , space can be saved, product size can be reduced, and production difficulty can be reduced.
  • FIG. 9 is a schematic structural diagram of a tunable laser 200 provided by an embodiment of the present application.
  • the embodiment of the second aspect of the present application provides a tunable laser 200 .
  • the tunable laser 200 includes the wavelength locker 100 as in the above embodiment, and further includes a light source module 210 .
  • the optical input end 140 of the wavelength locker 100 may be provided with a third connection end, and the optical input end 140 is connected to the light source module 210 through the third connection end to receive the light beam emitted from the light source module 210 , so that the light beam emitted by the light source module 210 can enter the ring resonant cavity through the light input end 140 and the second connection end.
  • the ring resonant cavity cooperates with the ring waveguide winding 110, the first beam splitter 120 and the second beam splitter 130, so that the light beam can resonate after entering the ring waveguide winding 110, forming a resonant beam, and realizing a certain free spectrum range
  • the comb-shaped transmission spectrum meets the precision requirement of the wavelength control of the tunable laser 200 . Since the light beam in the wavelength locker 100 comes from the light beam emitted by the light source module 210 , that is, the light beam emitted by the tunable laser 200 , the light beam entering the wavelength locker 100 has the wavelength characteristics of the tunable laser 200 .
  • the optical input terminal 140 is provided with a first connection terminal and a second connection terminal.
  • the first photodetector 220 is connected to the first connection end, receives part of the light emitted from the light source module 210, and generates a first photoelectric signal, while another part of light from the light source module 210 is output from the second connection end, and enters the ring resonant cavity , the filtered transmitted light is received by the second photodetector to generate a second photoelectric signal. Therefore, when the tunable laser 200 works at the desired wavelength, the first photodetector 220 and the second photodetector 221 respectively receive the light from the light source module 210, and the ratio of the generated first photoelectric signal to the second photoelectric signal is Value.
  • the ratio of the second photoelectric signal to the first photoelectric signal is used as the wave-locking signal of the working wavelength of the tunable laser 200, that is, the working wavelength of the tunable laser 200 shifts, and the wave-locking signal changes accordingly, so that the tunable laser can be adjusted 200 wavelength characteristics are monitored.
  • the phase modulator 230 is arranged on the ring waveguide winding 110 in the wavelength locker 100, so that the temperature of the ring waveguide winding 110 can be adjusted by controlling the phase modulator 230, and the refractive index of the ring waveguide winding 110 can be changed, thereby changing the ring resonant cavity
  • the wavelength of the tunable laser 200 is adjusted and the working point of the wave-locking signal is adjusted to a preset target position, thereby realizing the wavelength adjustment and locking of the tunable laser 200 .
  • the wavelength locker 100 can integrate the optical input terminal 140, the ring resonant cavity, the first photodetector 220, the second photodetector 221 and the phase modulator 230 on the SOI chip, without the need for an external body-type F-P etalon, Large-scale components such as gratings and filter arrays can realize the wavelength monitoring, adjustment and locking functions of the tunable laser 200, reduce the noise interference generated by the light source of the laser device, improve the adjustment accuracy, and save the structure of the wavelength locker 100 The space can reduce the size of the product, and at the same time reduce the complexity of the packaging process and reduce the cost.
  • the wavelength locker 100 is also provided with a first temperature measurement unit 250, and the first temperature measurement unit 250 is located in the wavelength locker 100.
  • the first temperature measurement unit 250 is a thermistor, which is mounted and integrated in the wavelength locker.
  • the metal electrodes on the SOI chip of the device 100 can be located inside or outside the ring resonant cavity.
  • the first temperature measurement unit 250 is integrated on the chip of the wavelength locker 100, so that the temperature change of the wavelength locker 100 can be monitored in real time, so as to precisely control the wavelength stability of the tunable laser 200, realize the functions of wavelength monitoring and locking, and at the same time reduce the The packaging volume of the laser 200 can be adjusted to reduce the cost.
  • the tunable laser 200 is also provided with an adjustable The temperature unit 240 is configured to adjust the temperature of the tunable laser 200, wherein the temperature adjustment unit 240 is a semiconductor refrigerator (Thermo Electric Cooler, TEC).
  • the light source module 210 of the tunable laser 200 is further provided with a second temperature measurement unit 260 configured to monitor temperature changes in the light source module 210 .
  • the temperature adjustment unit 240 can simultaneously adjust the temperature of the tunable laser 200, the first temperature measurement unit 250 acquires the first temperature data of the wavelength locker 100, and the second The temperature measurement unit 260 acquires the second temperature data of the tunable laser 200, can monitor the temperature change of the wavelength locker 100 and the light source module 210, can monitor the wavelength change of the tunable laser 200 and perform wavelength control and stabilization, thereby realizing wavelength locking. Function.
  • the light source module 210 includes a gain chip 211 (Gain Chip, GC) and an external cavity filter 212, wherein the gain chip 211 can be a semiconductor optical amplifier, and the external cavity filter 212 can be a periodic narrowband micro-ring filter device.
  • the gain chip 211 and the chip with the external cavity filter 212 are mounted on the substrate to form a light-emitting structural unit of the tunable laser 200 .
  • the wavelength locker 100 is integrated on the same SOI chip as the external cavity filter 212 , so as to receive the light beam emitted by the light source module 210 .
  • a phase modulator 230 and a first temperature measurement unit 250 are also arranged on the SOI chip of the external cavity filter 212 .
  • the temperature adjustment unit 240 is arranged under the substrate of the gain chip 211 and the external cavity filter 212 , so as to facilitate the temperature control of the tunable laser 200 .
  • the gain chip 211 may also be provided with a second temperature measurement unit 260 configured to monitor the temperature of the tunable laser 200 .
  • an embodiment of the present application provides a flow chart of a wavelength locking control method.
  • the wavelength locking control method is applied to a tunable laser, and the tunable laser includes the wavelength locker of the above-mentioned embodiment;
  • the light source module, the optical input end is connected to the light source module and receives the light beam from the light source module, and the wavelength locking control method includes the following steps:
  • Step S1010 acquiring the first photoelectric signal output by the first photodetector and the second photoelectric signal output by the second photodetector;
  • Step S1020 obtaining a wave-locking signal according to the first photoelectric signal and the second photoelectric signal
  • Step S1030 controlling the phase modulator according to the wave-locking signal to adjust the operating point of the wave-locking signal to a preset target position.
  • the wavelength locker includes a ring resonant cavity, an optical input end, a first photodetector, a second photodetector, and a phase modulator.
  • the ring resonant cavity includes a ring waveguide winding, and a first beam splitter and a second beam splitter respectively connected to the ring waveguide winding.
  • the light input end is connected with the light source module, receives the partial light beam emitted from the light source module, and is provided with a first connection end and a second connection end configured to emit light.
  • the first photodetector is connected to the first connection end, receives part of the light emitted from the light source module, and generates a first photoelectric signal, while the other part of light from the light source module is output from the second connection end, enters the ring resonant cavity, and is filtered
  • the last transmitted light is received by the second photodetector to generate a second photoelectric signal.
  • the first beam splitter and the second beam splitter are respectively connected with the ring waveguide, which can make the light beam enter the ring resonant cavity and transmit it resonantly, so that a comb-shaped transmission spectrum with FSR below 25 GHz can be realized, so that the wavelength locker can achieve high Precision wavelength control and stabilization.
  • the light beam entering the wavelength locker has the wavelength characteristic of the tunable laser. Therefore, when the tunable laser works at the desired wavelength, the first photodetector and the second photodetector respectively receive the light from the light source module, and process the generated first photoelectric signal and the second photoelectric signal to obtain the available
  • the wave-locking signal for adjusting the working wavelength of the laser, that is, the working wavelength of the tunable laser shifts, and the working point of the wave-locking signal changes accordingly, so that the wavelength characteristics of the tunable laser can be monitored.
  • operations such as addition, subtraction, multiplication or division may be performed on the first photoelectric signal and the second photoelectric signal to filter out some interference parameters to obtain a wave-locked signal.
  • the phase modulator is set on the ring waveguide winding in the wavelength locker, so that the temperature of the ring waveguide winding can be adjusted by controlling the phase modulator, the refractive index of the ring waveguide winding can be changed, and the wavelength movement of the wavelength locker can be adjusted.
  • the operating point of the wave signal is set on the ring waveguide winding in the wavelength locker, so that the temperature of the ring waveguide winding can be adjusted by controlling the phase modulator, the refractive index of the ring waveguide winding can be changed, and the wavelength movement of the wavelength locker can be adjusted.
  • the loading power of the phase modulator to adjust the working point of the wave-locking signal to the preset target position, that is, the wavelength corresponding to the working point at this time is the working wavelength of the tunable laser, so as to realize the wavelength monitoring and wavelength of the tunable laser. locking.
  • step S1020 in the embodiment shown in FIG. 10 also includes but is not limited to the following steps:
  • step S1021 according to the ratio relationship between the second photoelectric signal and the first photoelectric signal, a wave-locking signal is obtained.
  • the first photodetector and the second photodetector respectively receive the light of the desired working wavelength from the light source module, and the generated first photoelectric signal and the second photoelectric signal
  • the ratio of the signals is constant.
  • the ratio of the second photoelectric signal to the first photoelectric signal is used as the wave-locking signal of the working wavelength of the tunable laser.
  • the phase modulator is set on the ring waveguide winding in the wavelength locker, so that according to the change of the wave-locking signal, the phase modulator is controlled to adjust the temperature of the ring waveguide winding, change the refractive index of the ring waveguide winding, and then adjust the wavelength locker
  • the wavelength moves and changes the working point of the wave-locked signal. Therefore, by adjusting the power of the phase modulator and adjusting the wavelength movement of the wavelength locker, the working point of the wave-locking signal is adjusted to the preset target position.
  • the wavelength corresponding to the working point is the working wavelength of the tunable laser.
  • the working wavelength of the tunable laser is adjusted to the preset target wavelength, so as to realize the wavelength monitoring and locking of the tunable laser.
  • the wave-locking signal is obtained, and the working point of the wave-locking signal is adjusted to the preset target position, so as to realize the wavelength monitoring and wavelength locking of the tunable laser, which can reduce errors and maintain reliability.
  • the output wavelength of the adjustable laser is stable, the accuracy of the adjustment is improved, and the reliability and stability of the channel wavelength are improved.
  • step S1030 in the embodiment shown in FIG. 10 also includes but is not limited to the following steps:
  • Step S1031 acquiring the first temperature data of the wavelength locker output by the first temperature measurement unit
  • Step S1032 controlling the phase modulator according to the first temperature data and the wave-locking signal to adjust the operating point of the wave-locking signal to a preset target position.
  • the phase modulator adjusts the temperature of the ring waveguide winding, changes the refractive index of the ring waveguide winding, and then adjusts the wavelength shift of the wavelength locker to change the working point of the wave locking signal.
  • the wave locking signal changes accordingly.
  • the wavelength locker is also equipped with a first temperature measurement unit, the first temperature measurement unit obtains the first temperature data in the wavelength locker, and can control the adjustment effect of the phase modulator.
  • the phase modulator can be controlled according to the first temperature data and the wave-locking signal, and the temperature change in the wavelength locker can be monitored, which is beneficial for the phase modulator to adjust the wavelength movement of the wavelength locker, and the wave-locking of the wavelength locker
  • the working point is adjusted to the preset target position to improve the accuracy of wavelength adjustment and locking.
  • step S1032 in the embodiment shown in FIG. 12 also includes but is not limited to the following steps:
  • Step S1033 acquiring the second temperature data of the light source module output by the second temperature measuring unit
  • Step S1034 according to the wave-locking signal, the first temperature data and the second temperature data, control the temperature adjustment unit and the phase modulator to adjust the working wavelength of the tunable laser to a preset target wavelength.
  • the tunable laser is also provided with a temperature regulation unit, arranged to regulate the temperature of the tunable laser.
  • a second temperature measurement unit is provided on the light source module of the adjustable laser to obtain second temperature data of the light source module, and is configured to monitor temperature changes in the light source module.
  • the temperature change of the wavelength locker and the light source module can be monitored according to the first temperature data and the second temperature data, and the temperature adjustment unit can be controlled according to the first temperature data and the second temperature data
  • the temperature is lowered to maintain the temperature of the tunable laser, so as to lock the tunable laser to work at the required wavelength, so that the wavelength can be controlled and stabilized.
  • the first photodetector and the second photodetector respectively receive the light from the light source module, and process the generated first photoelectric signal and the second photoelectric signal to obtain a tunable laser
  • the wave-locking signal of the working wavelength when the temperature changes make the working wavelength of the tunable laser shift, the working point of the wave-locking signal changes accordingly, so that when the temperature adjustment unit maintains the temperature of the tunable laser, the phase modulator Adjust the wavelength movement of the wavelength locker, and adjust the working point of the locking signal to the preset target position.
  • the wavelength corresponding to the working point is the working wavelength of the tunable laser, that is, adjust the working wavelength of the tunable laser to the preset target wavelength.
  • the first temperature measurement unit, the second temperature measurement unit and the temperature adjustment unit cooperate with each other to realize the stability and accuracy of wavelength adjustment and locking of the tunable laser.
  • FIG. 14 is a schematic diagram of the effect of the wavelength locking method provided by an embodiment of the present application.
  • the solid line curve is the wave-locking signal curve of the tunable laser
  • the dotted line curve is the wave-locking signal curve of the wavelength redshift caused by the temperature rise of the tunable laser
  • the ordinate is the ratio of the second photoelectric signal to the first photoelectric signal
  • the preset target position is the working point of the selected wavelength locker
  • the abscissa corresponding to the working point is the target wavelength, that is, the required working wavelength of the tunable laser.
  • the first photodetector and the second photodetector respectively receive the light from the light source module, and generate the first photoelectric signal and the second photoelectric signal
  • the ratio of is a fixed value.
  • the ratio of the second photoelectric signal to the first photoelectric signal is used as the wave-locking signal of the working wavelength of the tunable laser, that is, the working wavelength of the tunable laser is shifted, and the wave-locking signal changes accordingly, so that the wavelength of the tunable laser can be adjusted characteristics are monitored.
  • the phase modulator is set on the ring waveguide winding in the wavelength locker, so that the temperature of the ring waveguide winding can be adjusted by controlling the phase modulator, and the refractive index of the ring waveguide winding can be changed, thereby changing the wavelength of the ring resonator and changing the locked wave The operating point of the signal.
  • the tunable laser works at the required wavelength, adjust the wavelength movement of the wavelength locker through the phase controller, and adjust the working point of the wave-locking signal to the preset target position, which is half of the peak value of the wave-locking signal curve, because the signal curve here
  • the range of change is large, and it has higher wave-locking precision.
  • the measured ratio of the second photoelectric signal to the first photoelectric signal deviates from a target value, thereby realizing wavelength monitoring.
  • the first temperature measurement unit monitors the temperature of the wavelength locker. With the long-term adjustment of the phase modulator, the temperature of the wavelength locker chip continues to rise, and the heat spreads to the surroundings, even causing the wavelength of the tunable laser to redshift. Therefore, At the same time, the temperature adjustment unit is controlled to adjust the temperature of the adjustable laser, and the second temperature measurement unit monitors the temperature change in the light source module.
  • the temperature adjustment unit of the tunable laser adjusts the temperature of the entire system
  • the first temperature measurement unit and the second temperature measurement unit monitor the temperature changes of the wavelength locker and the light source module respectively
  • Embodiments of the present application include: a wavelength locker, an adjustable laser, and a wavelength locking control method.
  • the wavelength locker is applied to an adjustable laser, and the adjustable laser is provided with a light source module configured to emit a beam of a required operating wavelength.
  • the wavelength locked The device includes a ring resonant cavity, an optical input end, a first photodetector, a second photodetector and a phase modulator; the optical input end is provided with a first connection end and a second connection end, which are configured to connect to the light source module and receive signals from The light beam of the light source module; the ring resonant cavity is connected to the second connection end, and is set to generate a comb-shaped transmission spectrum, including a ring waveguide winding, and a first beam splitter and a second beam splitter respectively connected to the ring waveguide winding ;
  • the first photodetector is connected to the first connection end, and is configured to receive a part of light from the light source module to generate
  • the optical input end can receive the light beam emitted from the light source module and divide it into two parts; a part of light is output from the first connection end, and the first photodetector can receive the light output from the first connection end , to generate the first photoelectric signal; the other part of the light is output from the second connection end, enters the ring resonant cavity, and is resonantly transmitted under the cooperation of the first beam splitter, the second beam splitter and the ring waveguide winding to generate a comb-shaped transmission spectrum .
  • the transmitted light filtered by the ring resonant cavity is received by the second photodetector to generate a second photoelectric signal.
  • the wave-locking signal of the tunable laser can be obtained according to the first photoelectric signal and the second photoelectric signal, and the wavelength offset of the tunable laser can be obtained according to the change of the wave-locking signal, so as to realize the function of wavelength monitoring; by controlling the phase modulator to adjust The working wavelength of the tunable laser is at the preset target wavelength to realize the function of wavelength locking. Therefore, a wavelength locker for tunable lasers can be realized through an optical input, a ring resonator, a phase modulator, a first photodetector, and a second photodetector without the need for external bulk etalons, gratings, or large filter arrays.
  • the component can realize the wavelength monitoring and adjustment and stabilization functions of the tunable laser, reduce the noise interference to the light source of the laser device, improve the adjustment accuracy, save the structural space of the wavelength locker, and reduce the complexity of the packaging process, thereby reducing the size of the tunable laser ,cut costs.

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Abstract

一种波长锁定器（100）、可调激光器（200）及波长锁定控制方法，该波长锁定器（100）包括环形谐振腔、光输入端（140）、第一光电探测器（220）、第二光电探测器（221）和相位调制器（230）；光输入端（140）设置有第一连接端和第二连接端；环形谐振腔与第二连接端连接，包括环形波导绕线（110），以及分别与环形波导绕线（110）连接的第一分束器（120）和第二分束器（130）；第一光电探测器（220）与第一连接端连接；第二光电探测器（221）与第一分束器（120）连接；相位调制器（230）设置于环形波导绕线（110）上。

Description

波长锁定器、可调激光器及波长锁定控制方法
相关申请的交叉引用
本申请基于申请号为202111066834.9、申请日为2021年09月13日的中国专利申请提出，并要求该中国专利申请的优先权，该中国专利申请的全部内容在此引入本申请作为参考。
技术领域
本申请涉及光电子设备技术领域，尤其涉及一种波长锁定器、可调激光器及波长锁定控制方法。
背景技术
为了满足通信网络和数据中心网络日益增长的带宽需求，密集波分复用(Dense Wavelength Division Multiplexing，DWDM)被认为是最有发展前景的技术之一。为了满足这一系统的发展需求，集成的可调激光器是关键。随着通道数目的增长，以及它们之间频率间隔的减小，高精度判断，实现各波长稳定控制成为可调激光器性能的关键技术，可以避免通道间的内部串扰。
尤其是用于波长锁定的标准具，预定义一个确定的波长网格用来监测和定标所设定通道的偏移量，从而调节激光器的驱动进行校准。而在一些情形下光通信系统中的参考标准具主要依靠自由空间的体材料，并且安装在可调激光器的输出端，或者作为一个独立的封装组件，从而限制了可调激光器的小型化发展，以及最终应用于DWDM光通信系统的可调光发射机的集成体积。
在一些情形下，实现波长锁定和监测的元器件种类很多，包括外置体型F-P标准具、光栅和滤波器阵列等，但是它们的体积大，需要复杂的控制系统，且存在较大的反射，会对激光器件光源产生较大的噪声干扰。因此，还需要在激光器件光路中增加体积较大的隔离器，使得可调激光器和波长锁定器都需要较大的体积，锁波精度不高，同时封装工艺复杂，成本增加，也限制了可调激光器的小型化发展。
发明内容
有鉴于此，本申请实施例提供一种波长锁定器、可调激光器及波长锁定控制方法。
第一方面，本申请实施例提供一种波长锁定器，应用于可调激光器，该可调激光器设置有被设置为发出具有所需工作波长光束的光源模块，该波长锁定器包括：光输入端，被设置为连接所述光源模块并接收来自所述光源模块的光束，所述光输入端还设置有第一连接端和第二连接端；环形谐振腔，与所述第二连接端连接，所述环形谐振腔包括环形波导绕线，以及分别与所述环形波导绕线连接的第一分束器和第二分束器，所述环形波导绕线、所述第一分束器与所述第二分束器被设置为配合产生梳状传输光谱；第一光电探测器，与所述第一连接端连接，被设置为接收来自所述光源模块所发出的光的一部分光以产生第一光电信号；第二光电探测器，与所述第一分束器连接，被设置为接收经所述环形谐振腔滤波后的透射光以 产生第二光电信号；相位调制器，设置于所述环形波导绕线上，被设置为调节所述环形谐振腔的相位。
第二方面，本申请实施例提供一种可调激光器，包括：第一方面所述的波长锁定器；还包括被设置为发出光束的光源模块，所述光输入端连接所述光源模块并接收来自所述光源模块的具有所需工作波长的光束。
第三方面，本申请实施例提供一种波长锁定控制方法，应用于可调激光器，所述可调激光器包括第一方面所述的波长锁定器；还包括被设置为发出具有所需工作波长的光束的光源模块，所述光输入端连接所述光源模块并接收来自所述光源模块的光束；该控制方法，包括：获取由所述第一光电探测器输出的第一光电信号和由所述第二光电探测器输出的第二光电信号；根据所述第一光电信号和所述第二光电信号得到锁波信号；根据所述锁波信号控制所述相位调制器将所述锁波信号的工作点调节至预设目标位置。
本申请的其它特征和优点将在随后的说明书中阐述，并且，部分地从说明书中变得显而易见，或者通过实施本申请而了解。本申请的目的和其他优点可通过在说明书、权利要求书以及附图中所特别指出的结构来实现和获得。
附图说明
附图用来提供对本申请技术方案的进一步理解，并且构成说明书的一部分，与本申请的实施例一起用于解释本申请的技术方案，并不构成对本申请技术方案的限制。
下面结合附图和实施例对本申请进一步地说明；
图1是本申请的一个实施例提供的波长锁定器的结构示意图；
图2是图1所示的波长锁定器的一个实施例对应的传输特性曲线的示意图；
图3是本申请的另一个实施例提供的波长锁定器的结构示意图；
图4是图3所示的波长锁定器的一个实施例对应的传输特性曲线的示意图；
图5是本申请的另一个实施例提供的波长锁定器的结构示意图；
图6是图5所示的波长锁定器的一个实施例对应的传输特性曲线的示意图；
图7是本申请另一个实施例提供的波长锁定器的安装方法的流程图；
图8是图7所示的波长锁定器的一个实施例对应的传输特性曲线的示意图；
图9是本申请的一个实施例提供的可调激光器的结构示意图；
图10是本申请一个实施例提供的波长锁定方法的流程图；
图11是图10步骤S1020的一种具体实现过程的流程图；
图12是图10步骤S1030的另一种具体实现过程的流程图；
图13是图12步骤S1032的另一种具体实现过程的流程图；
图14是本申请一个实施例提供的波长锁定方法的效果示意图。
附图标记：波长锁定器100、环形波导绕线110、第一分束器120、第二分束器130、光输入端140、可调激光器200、光源模块210、增益芯片211、外腔滤波器212、第一光电探测器220、第二光电探测器221、相位调制器230、调温单元240、第一测温单元250、第二测温单元260。
具体实施方式
本部分将详细描述本申请的具体实施例，本申请之若干实施例在附图中示出，附图的作用在于用图形补充说明书文字部分的描述，使人能够直观地、形象地理解本申请的每个技术特征和整体技术方案，但其不能理解为对本申请保护范围的限制。
在本申请的描述中，若干的含义是一个或者多个，多个的含义是两个以上，大于、小于、超过等理解为不包括本数，以上、以下、以内等理解为包括本数。如果有描述到第一、第二只是用于区分技术特征为目的，而不能理解为指示或暗示相对重要性或者隐含指明所指示的技术特征的数量或者隐含指明所指示的技术特征的先后关系。
本申请的描述中，除非另有明确的限定，设置、安装、连接等词语应做广义理解，所属技术领域技术人员可以结合技术方案的具体内容合理确定上述词语在本申请中的具体含义。
本申请实施例提供一种波长锁定器、可调激光器及波长锁定控制方法，其中，光输入端能够接收光源模块的光束，第一分束器和第二分束器分别与环形波导绕线连接，来自光源模块的光束，一部分光从第一连接端输出，被第一光电探测器接收，产生第一光电信号；另一部分光从第二连接端输出，进入环形谐振腔，经滤波后的透射光被第二光电探测器接收，产生第二光电信号。根据第一光电信号和第二光电信号的变化情况能够获取可调激光器波长偏移情况，实现波长监测的功能；通过控制相位调制器以调节可调激光器的工作波长在预设目标波长，实现波长锁定的功能。因此，通过光输入端、环形谐振腔、第一光电探测器、第二光电探测器和相位调制器的相互配合，无需采用外置体型标准具、光栅或滤波器阵列大型空间结构元件就能够实现可调激光器波长调节和监测功能，降低对激光器件光源产生噪声干扰，提高调节精度，节省了波长锁定器的结构空间，降低封装工艺的复杂度，从而缩小可调激光器的尺寸，降低成本。
下面结合附图，对本申请实施例作进一步阐述。
如图1所示，图1是本申请的一个实施例提供的波长锁定器100的结构示意图，本申请的实施例提供一种波长锁定器100，应用于可调激光器200，该可调激光器200设置有光源模块210，光源模块210能够发出具有所需工作波长的光束。
可以理解的是，波长锁定器100包括环形谐振腔、光输入端140、第一光电探测器220、第二光电探测器221、相位调制器230。其中，环形谐振腔包括环形波导绕线110，以及分别与环形波导绕线110连接的第一分束器120和第二分束器130。光输入端140还可以设置有第三连接端，光输入端140通过第三连接端与光源模块210连接，接收来自于光源模块210发出的部分光束，设置有第一连接端和第二连接端。第一光电探测器220与第一连接端连接，接收来自光源模块210发出的光的一部分，产生第一光电信号，而来自光源模块210的另一部分光从第二连接端输出，进入环形谐振腔，经滤波后的透射光被第二光电探测器接收，产生第二光电信号。第一分束器120和第二分束器130分别与环形波导绕线110连接，能够使得光束进入环形谐振腔后谐振传输，从而实现具有25GHz以下自由频谱范围(Free Spectral Range，FSR)的梳状传输光谱，使得波长锁定器100能够实现高精度的波长控制和稳定。由于波长锁定器100内的光束来自于光源模块210所发出的光束，即来自于可调激光器200所发出的光束，从而进入波长锁定器100内的光束具有可调激光器200的波长特性。因此，在可调激光器200工作在所需波长时，第一光电探测器220和第二光电探测器221分别接收来自光源模块210的相应功率的光，分别生成第一光电信号和第二光电信号。当可调激光器200 的工作波长发生偏移，第一光电信号和第二光电信号随之变化，从而能够实现对可调激光器200的波长特性进行监测。相位调制器230设置在波长锁定器100内环形波导绕线110上，从而能够通过控制相位调制器230调节环形波导绕线110的温度，改变环形波导绕线110的折射率，进而改变环形谐振腔的波长，将锁波信号的工作点调节至预设目标位置，从而能够通过波长锁定器100实现可调激光器200的波长调节和锁定。在一些情形下，采用外置体型F-P标准具，光栅，滤波器阵列等也能够实现激光器波长锁定和监测的功能，但由于它们体积大，需要复杂的控制系统，且存在较大的反射，对激光器的光源产生严重的噪声干扰，从而，还需要在激光器中添加体积较大的隔离器。因此，波长锁定器100可以通过将光输入端140、环形谐振腔、第一光电探测器220、第二光电探测器221和相位调制器230集成在SOI芯片上，无需外置体型F-P标准具，光栅，滤波器阵列等大型元件，就能够实现可调激光器200的波长监测、调节和锁定的功能，减少了对激光器件光源产生的噪声干扰，提高了调节精度，节省了波长锁定器100的结构空间，能够缩小产品尺寸，同时降低封装工艺复杂度，降低成本。
需要说明的是，第一分束器120和第二分束器130可以是定向耦合器，也可以是多模干涉仪，而环形波导绕线110可以是氮化硅波导绕线，即SiN波导绕线，也可以是深刻蚀硅波导绕线，能够根据不同的使用场景采用不同的波导绕线或调节分束器的分光比。
可以理解的是，波长锁定器100还设置第一测温单元250，第一测温单元250位于波长锁定器100内，其中波长锁定器100内还设置有金属电极，金属电极用于贴装固定第一测温单元250，而金属电极可以位于环形谐振腔的内侧，也可以位于环形谐振腔的外侧。因此，将第一测温单元250集成贴装在波长锁定器100的芯片上，获取波长锁定器100的第一温度数据，能够实时监测波长锁定器100的温度变化，从而精确控制可调激光器200的波长稳定，有利于实现波长锁定器100的波长监测和锁定功能，同时可以缩小可调激光器200的封装体积，降低成本。
需要说明的是，可调激光器200还设置有调温单元240，被设置为控制可调激光器200的温度，同时还可以控制波长锁定器100的温度。另外在可调激光器200的光源模块210上还设置有第二测温单元260，被设置为监测光源模块210内的温度变化。因此，在调温单元240调节可调激光器200的温度，第一测温单元250和第二测温单元260分别监测波长锁定器100和光源模块210温度变化的情况下，可以监测可调激光器200的波长变化，协同进行波长控制和稳定，实现波长锁定的功能。
可以理解的是，波长锁定器100和可调激光器200可以集成在同一硅基芯片上，即SOI(Silicon-on-Insulator，SOI)芯片上。在一些情形下，外置参考标准具体积大，需要安装在可调激光器200的输出端，但由于基于片外参考标准具的波长锁定组件和可调激光器200之间的尺寸不匹配，需要混合集成，或将参考标准具进行独立控制和贴装，从而提高了控制系统和封装工艺复杂度，降低了可靠性，增加了成本。因此，通过将波长锁定器100和可调激光器200集成在同一SOI片上，不需要独立封装光学元件，能够缩小产品尺寸，降低封装工艺复杂度，还能够避免波长锁定器100独立封装而降低波长锁定器100机械振动的可靠性和温度的灵敏度，提高调节精度和稳定性。另外，由于将波长锁定器100和可调激光器200 集成在同一SOI片上，因此不需要放置波长锁定器100于可调激光器200的输出端，降低了波长锁定器100对外部光学反馈的影响，提高波长锁定器100的稳定性。
如图2所示，图2是图1所示的波长锁定器100的一个实施例提供对应的传输特性曲线的示意图，图2中所示的PD2曲线，即虚线，为第一光电探测器220的传输特性曲线；而所示的PD3曲线，即实线，为第二光电探测器221的传输特性曲线。
结合图2，可以理解的是，环形波导绕线110能够通过光输入端140接收光源模块210所发出的光束，光输入端140可以是第一反射镜与分束元件组成，第一反射镜与分束元件相耦合，即，第一反射镜与分束元件相配合实现光耦合分束，第一反射镜和分束元件对同一波长的光功率进行分路，其中，分束元件可以是定向耦合器，从而，光输入端140所接收到的光能够通过第一反射镜进行分路，分束元件能够接收到由第一反射镜分出的部分光。例如，定向耦合器可以在波长为1550米处设置分光比为85:15，光输入端140上分别设置有第一连接端和第二连接端，因此，第一连接端和第二连接端各有15％的光束出射，而第一连接端与第一光电探测器220连接，第二连接端与环形谐振腔连接，可以在波长为1550nm处设置第一连接端与第二连接端的分光比为40:60。因此，从第一连接端出射的40％光束被第一光电探测器220接收，从第二连接端出射的60％光束进入环形谐振腔,形成谐振光束，而第一分束器120中的直通端与第二光电探测器221相连接，接收周期性谐振透射光。第一分束器120和第二分束器130的分光比相同，设置为0.75，因此，进入第一分束器120的光束中有25％的谐振光束进入第二光电探测器221，从而，在波长1550nm处，第一光电探测器220的输入光功率与第二光电探测器的输入光功率的比值为8:3，得到波长锁定器100的传输性能数据，便于进行后续的波长调节，提高波长锁定器100的稳定性和可靠性。另外，波长锁定器100的FSR可以设置为25GHz，第一反射镜为深刻蚀硅波导元件，环形谐振腔包括环形波导绕线110，第一分束器120和第二分束器130，为氮化硅波导元件，氮化硅波导高度为400nm，典型宽度为1μm，波导绕线的宽度为2μm，从1μm到2μm的渐变波导长度为40μm，氮化硅波导的群折射率为1.985，波导绕线的长度可以通过如下波导长度关系式计算得出：
Figure PCTCN2022106287-appb-000001
其中，L为波导绕线长度，λ为波长，FSR为自由频谱范围，n g为群折射率。
因此，可以计算得到在FSR为25GHz的波长锁定器100波导绕线所对应的长度为6063.5μm。从图2可以看出，第一光电探测器220所对应的传输特性曲线为0.4的直线，第二光电探测器221所对应的传输特性曲线为0.35至0.6之间的周期性梳状曲线，因此可以将第二光电探测器221产生的第二光电信号与第一光电探测器220产生的第一光电信号比值处理得到锁波信号，得到的锁波信号也为周期性梳状曲线，能够实现25GHz以下的波长间隔，因而可达到可调激光器200的波长控制的精度要求。波长锁定器100能够根据波导绕线的群折射率和所需的光束波长，调节波导绕线的长度来调节所需的FSR，或者能够根据波导绕线的群折射率和所需的光束波长，调节FSR以调节波导绕线的长度。波长锁定器100的结构设计灵活，可以调节波导绕线长度和绕线方式，节省结构空间，缩小产品尺寸，也可以调节FSR，适用于不同的使用场景，提高调节精度和波长稳定性。
如图3和图4所示，图3是本申请的另一个实施例提供的波长锁定器100的结构示意图； 图4是图3所示的波长锁定器100的一个实施例提供对应的传输特性曲线的示意图，图4所示的PD2曲线，即虚线，为第一光电探测器220的传输特性曲线；而所示的PD3曲线，即实线，为第二光电探测器221的传输特性曲线。光输入端140可以是第二反射镜与第三反射镜耦合组成，即，第二反射镜与第三反射镜之间能够组成定向耦合器，对同一波长的光功率进行分路，其中，第二反射镜和第三反射镜中均为环形反射镜，例如，光输入端140所接收到的光能够通过第二反射镜进行分路，第三反射镜能够接收到由第二反射镜分出的部分光并进行传输。
结合图3和图4，可以理解的是，光输入端140可以由不同的光学元件组成，从而能够根据不同的使用场景而选择不同的光输入端140类型，结构设计灵活，适应性强，并且所采用的元件数量少，体积小，降低生产复杂度，缩小产品尺寸。例如，第二反射镜和第三反射镜之间通过第一定向耦合器连接，分光比为90：10，即第二反射镜将从光源模块210输出光束中的10％光束耦合到第三反射镜，在第三反射镜上设置第一端口，被设置为输出第三反射镜中的部分光，在第一端口与环形谐振腔之间设置有分光比为80:20的第二定向耦合器，第二定向耦合器上设置有第二端口和第三端口，第二端口与第一光电探测器220连接，接收来自第一端口光束中20％的光束，第三端口与环形谐振腔连接，接收来自第一端口光束中80％的光束。第一分束器120和第二分束器130的分光比可以设置为相同，分光比设置为25:75，因此，进入环形谐振腔的光束中有25％的光束能够进入第二光电探测器221，因此，在波长1550nm处，第一光电探测器220的输入光功率与第二光电探测器221的输入光功率的比值为1:1，从而，可以根据所需的波长锁定器100性能数据，调节光输入端140的组件，或者调节第一分束器120的分光比，便于进行后续的波长调节，提高波长锁定器100的灵敏度和稳定性。另外，波长锁定器100的FSR可以设置为25GHz，第二反射镜为深刻蚀硅波导元件，环形谐振腔包括环形波导绕线110，第一分束器120和第二分束器130，为氮化硅波导元件，氮化硅波导高度为400nm，典型宽度为1μm，波导绕线的宽度为2μm，从1μm到2μm的渐变波导长度为40μm，氮化硅波导绕线的群折射率为1.985，波动绕线的长度可以通过上述实施例中的波导长度关系式进行计算得出，在FSR长度为25GHz的波长锁定器100波导绕线所对应的长度为6063.5μm。从图4可以看出，第一光电探测器220所对应的传输特性曲线为0.2的直线，第二光电探测器221所对应的传输特性曲线为0.5至0.8之间的周期性梳状曲线，因此将第二光电探测器221产生的第二光电信号与第一光电探测器220产生的第一光电信号比值处理得到锁波信号，锁波信号也为周期性梳状曲线，能够实现25GHz以下的波长间隔，因而可达到可调激光器200的波长控制的精度要求。因此，波长锁定器100即使选择不同元件组成的光输入端140，调节光输入端140的分光比，波长锁定器100都能够实现25GHz的波长精度。波长锁定器100能够根据实际情况选择光输入端140的类型，调节光输入端140的分光比或者调节第一分束器120的分光比，结构设计灵活，体积小，能够提高调节精度和波长稳定性。
如图5和图6所示，图5是本申请的另一个实施例提供的波长锁定器100的结构示意图；图6是图5所示的波长锁定器100的一个实施例提供对应的传输特性曲线的示意图，图6所示的PD2曲线，即虚线，为第一光电探测器220的传输特性曲线；而所示的PD3曲线，即实线，为第二光电探测器221的传输特性曲线。光输入端140可以是第四反射镜，第四反射镜设置有第三定向耦合器和第四端口，被设置为输出从可调激光器200的光源模块210分出的 部分光。
可以理解的是，光输入端140可以仅采用第四反射镜，环形波导绕线110可以通过第四反射镜接收来自于光源模块210的光束，结构简单，节省空间，能够缩小产品尺寸，降低生产难度。而光输入端140采用第四反射镜，通过调节第四反射镜的分光比，能够调节波长锁定器100的性能数据，在保持小体积的优势的同时，也能够实现高精度的调节功能。例如，第四反射镜上的第三定向耦合器在波长为1550nm处的分光比为25：75，因此，有25％的光束从第四端口出射，进入分光比为75:25的第四定向耦合器，第四定向耦合器上设置第一连接端和第二连接端；即从第四端口出射的光，有25％的光束从第一连接端输出被第一光电探测器220接收，有75％的光束从第二连接端输出，进入环形谐振腔内，形成谐振光束。环形谐振腔中第一分束器120和第二分束器130的分光比均为25:75，即第二光电探测器221能够接收到来自第二连接端的光束的25％。因此，在波长1550nm处，第一光电探测器220的输入光功率与第二光电探测器221的输入光功率的比值为4:3。通过选择不同元件组成的光输入端140，能够调节第一连接端的输入光功率与第二连接端的输入光功率的比值，结构设计灵活，能够根据实际需求选择不同类型的光输入端140，降低工艺复杂度，提高波长锁定器100的灵敏度和稳定性。从图6可以看出，第一光电探测器220所对应的传输特性曲线为0.25的直线，第二光电探测器221所对应的传输特性曲线为0.4至0.7之间的周期性梳状曲线，因此将第二光电探测器221产生的第二光电信号与第一光电探测器220产生的第一光电信号比值处理得到锁波信号，所得到的锁波信号也为周期性梳状曲线，能够实现25GHz以下的波长间隔，因而可达到可调激光器200的波长控制的精度要求。而且当第四反射镜为深刻蚀硅波导元件，环形谐振腔包括环形波导绕线110，第一分束器120和第二分束器130，为氮化硅波导元件，氮化硅波导高度为400nm，典型宽度为1μm，波导绕线的宽度为2μm，从1μm到2μm的渐变波导长度为40μm，氮化硅波导绕线的群折射率为1.985，波导绕线长度设置为6063.5μm，能够实现25GHz的FSR。因此，波长锁定器100的结构设计灵活简单，体积小，能够实现高精度的波长控制，提高了稳定性和可靠性。
如图7和图8所示，图7是本申请的另一个实施例提供的波长锁定器100的结构示意图；图8是图5所示的波长锁定器100的一个实施例提供对应的传输特性曲线的示意图，图8所示的PD2曲线，即虚线，为第一光电探测器220的传输特性曲线；而所示的PD3曲线，即实线，为第二光电探测器221的传输特性曲线。光输入端140可以是相耦合的第一反射镜与分束元件，即，第一反射镜与分束元件相配合实现光耦合分束，第一反射镜和分束元件对同一波长的光功率进行分路，其中，分束元件可以是定向耦合器，从而，光输入端140所接收到的光能够通过第一反射镜进行分路，分束元件能够接收到由第一反射镜分出的部分光并进行传输，其中，第一反射镜为深刻蚀硅波导元件，波导绕线为深刻蚀硅波导元件。
结合图7和图8，可以理解的是，光输入端140可以采用不同元件组成，也可以采用更换不同组成元件的材质，从而适用于不同的使用场景，缩小产品尺寸，提高稳定性和可靠性。例如，定向耦合器可以在波长为1550米处设置分光比为85:15，光输入端140上分别设置有第一连接端和第二连接端，第一连接端与第一光电探测器220连接，第二连接端与环形谐振腔连接，可以在波长为1550nm处设置第一连接端与第二连接端的分光比为40:60。因此，从第一连接端出射的40％光束被第一光电探测器220接收，从第二连接端出射的60％光束进入环形谐振腔,形成谐振光束，而第一分束器120中的直通端与第二光电探测器221相连接，接收 周期性谐振透射光。第一分束器120和第二分束器130的分光比相同，设置为0.75，因此，进入第一分束器120的光束中有25％的谐振光束进入第二光电探测器221，从而，在波长1550nm处，第一光电探测器220的输入光功率与第二光电探测器221的输入光功率的比值为8:3，从图8可以看出，第一光电探测器220所对应的传输特性曲线为0.4的直线，第二光电探测器221所对应的传输特性曲线为0.35至0.6之间的周期性梳状曲线，因此，说明在通过采用相同元件组成光输入端140，设置相同的分光比的情况下，更换不同材质的波导绕线和不同材质的反射镜，不影响波长锁定器100的性能，因此，具有高稳定性和高可靠性。另外，由于第一反射镜为深刻蚀硅波导元件，环形谐振腔包括环形波导绕线110，第一分束器120和第二分束器130为深刻蚀硅元件，硅波导高度为220nm，深刻蚀厚度为90nm，波导宽度为500nm，群折射率为3.894，在自由频谱范围设置为25GHz的情况下，波导绕线的长度为3084.87μm。因此，可以通过更换组成波长锁定器100的元件的材质，节省空间，能够缩小产品尺寸，降低生产难度。
如图9所示，图9是本申请的一个实施例提供的可调激光器200的结构示意图。本申请的第二方面实施例提供一种可调激光器200，可调激光器200包括如上述实施例中的波长锁定器100，还包括光源模块210。
结合图9，可以理解的是，波长锁定器100的光输入端140可以设置有第三连接端，光输入端140通过第三连接端与光源模块210连接，接受来自于光源模块210发出的光束，从而光源模块210发出的光束能够通过光输入端140和第二连接端进入环形谐振腔内。环形谐振腔通过环形波导绕线110、第一分束器120和第二分束器130的相互配合，使得光束进入环形波导绕线110后能够进行谐振，形成谐振光束，实现在一定自由频谱范围的梳状传输光谱，达到可调激光器200的波长控制的精度要求。由于波长锁定器100内的光束来自于光源模块210所发出的光束，即来自于可调激光器200所发出的光束，从而进入波长锁定器100内的光束具有可调激光器200的波长特性。光输入端140设置有第一连接端和第二连接端。第一光电探测器220与第一连接端连接，接收来自光源模块210发出的光的一部分，产生第一光电信号，而来自光源模块210的另一部分光从第二连接端输出，进入环形谐振腔，经滤波后的透射光被第二光电探测器接收，产生第二光电信号。因此，在可调激光器200工作在所需波长时，第一光电探测器220和第二光电探测器221分别接收来自光源模块210的光，产生的第一光电信号和第二光电信号的比值为定值。将第二光电信号与第一光电信号的比值作为可调激光器200工作波长的锁波信号，即可调激光器200所在工作波长发生偏移，锁波信号随之变化，从而能够实现对可调激光器200的波长特性进行监测。相位调制器230设置在波长锁定器100内环形波导绕线110上，从而能够通过控制相位调制器230调节环形波导绕线110的温度，改变环形波导绕线110的折射率，进而改变环形谐振腔的波长，将锁波信号的工作点调节至预设目标位置，进而实现可调激光器200的波长调节和锁定。因此，波长锁定器100可以通过将光输入端140、环形谐振腔、第一光电探测器220、第二光电探测器221和相位调制器230集成在SOI芯片上，无需外置体型F-P标准具，光栅，滤波器阵列等大型元件，就能够实现可调激光器200的波长监测、调节和锁定的功能，减少了对激光器件光源产生的噪声干扰，提高了调节精度，节省了波长锁定器100的结构空间，能够缩小产品尺寸，同时降低封装工艺复杂度，降低成本。
可以理解的是，波长锁定器100还设置第一测温单元250，第一测温单元250位于波长 锁定器100内，例如，第一测温单元250是热敏电阻，贴装集成在波长锁定器100的SOI芯片上的金属电极上，可以位于环形谐振腔的内侧，也可以位于环形谐振腔的外侧。将第一测温单元250集成在波长锁定器100的芯片上，可以实时监测波长锁定器100的温度变化，从而精确控制可调激光器200的波长稳定，实现波长监测和锁定的功能，同时可以缩小可调激光器200的封装体积，降低成本。而相位调制器230在调节波长的过程中，波长锁定器100芯片的温度不断升高，热量扩散到四周，甚至使得可调激光器200的波长发生红移，因此，可调激光器200还设置有调温单元240，被设置为调节可调激光器200的温度，其中，调温单元240是半导体制冷器(Thermo Electric Cooler，TEC)。另外在可调激光器200的光源模块210上还设置有第二测温单元260，被设置为监测光源模块210内的温度变化。因此在相位调制器230调节波长锁定器100的相位的过程中，调温单元240能够同时调节可调激光器200的温度，第一测温单元250获取波长锁定器100的第一温度数据，第二测温单元260获取可调激光器200的第二温度数据，能够监测波长锁定器100和光源模块210的温度变化，可以监测可调激光器200的波长变化并进行波长控制和稳定，从而实现波长锁定的功能。
需要说明的是，光源模块210包括增益芯片211(Gain Chip，GC)和外腔滤波器212，其中，增益芯片211可以是半导体光放大器，而外腔滤波器212可以是周期性窄带微环滤波器。增益芯片211和带有外腔滤波器212的芯片贴装在衬底基片上，构成可调激光器200的发光结构单元。波长锁定器100集成于与外腔滤波器212同一SOI芯片上，从而能够接收光源模块210所发出的光束。在外腔滤波器212的SOI芯片上还设置有相位调制器230和第一测温单元250。而调温单元240设置在增益芯片211和外腔滤波器212的衬底基片的下方，从而便于控制可调激光器200的温度。同时，增益芯片211上还可以设置有第二测温单元260，被设置为监测可调激光器200的温度。
参照图10，本申请的一个实施例提供一种波长锁定控制方法的流程图，波长锁定控制方法应用于可调激光器，可调激光器包括上述实施例的波长锁定器；还包括被设置为发出光束的光源模块，光输入端连接光源模块并接收来自光源模块的光束，波长锁定控制方法包括以下步骤：
步骤S1010，获取由第一光电探测器输出的第一光电信号和由第二光电探测器输出的第二光电信号；
步骤S1020，根据第一光电信号和第二光电信号得到锁波信号；
步骤S1030，根据锁波信号控制相位调制器将锁波信号的工作点调节至预设目标位置。
可以理解的是，波长锁定器包括环形谐振腔、光输入端、第一光电探测器、第二光电探测器、相位调制器。其中，环形谐振腔包括环形波导绕线，以及分别与环形波导绕线连接的第一分束器和第二分束器。光输入端与光源模块连接，接收来自于光源模块发出的部分光束，并且设置有被设置为出射光的第一连接端和第二连接端。第一光电探测器与第一连接端连接，接收来自光源模块发出的光的一部分，产生第一光电信号，而来自光源模块的另一部分光从第二连接端输出，进入环形谐振腔，经滤波后的透射光被第二光电探测器接收，产生第二光电信号。第一分束器和第二分束器分别与环形波导绕线连接，能够使得光束进入环形谐振腔后谐振传输，从而可以实现具有25GHz以下FSR的梳状传输光谱，使得波长锁定器能够实现 高精度的波长控制和稳定。由于波长锁定器内的光束来自于光源模块所发出的光束，即来自于可调激光器所发出的光束，从而进入波长锁定器内的光束具有可调激光器的波长特性。因此，在可调激光器工作在所需波长时，第一光电探测器和第二光电探测器分别接收来自光源模块的光，对产生的第一光电信号和第二光电信号进行处理，得到作为可调激光器工作波长的锁波信号，即可调激光器所在工作波长发生偏移，锁波信号的工作点随之变化，从而能够实现对可调激光器的波长特性进行监测。其中，可以对第一光电信号与第二光电信号进行相加、相减、相乘或相除等运算处理，滤除部分干扰参数，得到锁波信号。相位调制器设置在波长锁定器内环形波导绕线上，从而能够通过控制相位调制器调节环形波导绕线的温度，改变环形波导绕线的折射率，进而调节波长锁定器的波长移动，调节锁波信号的工作点。因此，调节相位调制器的加载功率，将锁波信号的工作点调节至预设目标位置，即此时工作点所对应的波长为可调激光器的工作波长，实现可调激光器的波长监测和波长锁定。
参照图11，图10所示实施例中的步骤S1020还包括但不限于有以下步骤：
步骤S1021，根据第二光电信号与第一光信号的比值关系，得到锁波信号。
可以理解的是，在可调激光器工作在所需波长时，第一光电探测器和第二光电探测器分别接收来自光源模块的所需工作波长的光，产生的第一光电信号和第二光电信号的比值为定值。为了提高控制的准确性和可靠性，将第二光电信号与第一光电信号的比值作为可调激光器工作波长的锁波信号，当可调激光器所在工作波长发生偏移，锁波信号的工作点随之变化，从而能够实现对可调激光器的波长特性进行监测。相位调制器设置在波长锁定器内环形波导绕线上，从而根据锁波信号的变化情况，控制相位调制器调节环形波导绕线的温度，改变环形波导绕线的折射率，进而调节波长锁定器的波长移动，改变锁波信号的工作点。因此，通过调节相位调制器的功率，调节波长锁定器的波长移动，将锁波信号的工作点调节至预设目标位置，此时工作点所对应的波长为可调激光器的工作波长，即将可调激光器的工作波长调节至预设目标波长，进而实现可调激光器的波长监测和锁定。而根据第二光电信号和第一光电信号的比值关系得到锁波信号，将锁波信号的工作点调节至预设目标位置，实现可调激光器的波长监测和波长锁定，能够降低误差，保持可调激光器输出波长稳定，提高调节的准确度，提高通道波长的可靠性和稳定性。
参照图12，图10所示实施例中的步骤S1030还包括但不限于有以下步骤：
步骤S1031，获取由第一测温单元输出的波长锁定器的第一温度数据；
步骤S1032，根据第一温度数据和锁波信号控制相位调制器将锁波信号的工作点调节至预设目标位置。
可以理解的是，相位调制器通过改变自身的加载功率，调节环形波导绕线的温度，改变环形波导绕线的折射率，进而调节波长锁定器的波长移动，改变锁波信号的工作点。当可调激光器所在工作波长发生变化，锁波信号随之变化。为了将波长锁定器的锁波工作点调节至预设目标位置，需要调节相位调制器的加载功率，改变环形波导绕线的温度。为了能够提高波长监测和锁定的准确性，波长锁定器还设置第一测温单元，第一测温单元获取波长锁定器内的第一温度数据，能够控制相位调制器的调节效果。因此，能够根据第一温度数据和锁波 信号对相位调制器进行控制，能够监测波长锁定器内的温度变化情况，有利于相位调制器调节波长锁定器的波长移动，将波长锁定器的锁波工作点调节至预设目标位置，提高波长调节和锁定的准确性。
参照图13，图12所示实施例中的步骤S1032还包括但不限于有以下步骤：
步骤S1033，获取由第二测温单元输出的光源模块的第二温度数据；
步骤S1034，根据锁波信号、第一温度数据和第二温度数据，控制调温单元和相位调制器将可调激光器的工作波长调节至预设目标波长。
可以理解的是，相位调制器在调节波长锁定器波长移动的过程中，波长锁定器芯片的温度不断升高，热量扩散到四周，甚至使得可调激光器的波长发生红移，波长锁定器的工作点随之变化。因此，可调激光器还设置有调温单元，被设置为调节可调激光器的温度。另外在可调激光器的光源模块上还设置有第二测温单元，获取光源模块的第二温度数据，被设置为监测光源模块内的温度变化。因此在相位调制器调节波长锁定器的波长的过程中，能够根据第一温度数据和第二温度数据监测波长锁定器和光源模块温度变化，根据第一温度数据和第二温度数据控制调温单元进行降温，维持可调激光器的温度，从而锁定可调激光器工作在所需波长，从而能够进行波长控制和稳定。在可调激光器工作在所需波长时，第一光电探测器和第二光电探测器分别接收来自光源模块的光，对产生的第一光电信号和第二光电信号进行处理，得到作为可调激光器工作波长的锁波信号，当温度变化使得可调激光器所在工作波长发生偏移时，锁波信号的工作点随之变化，从而，在调温单元维持可调激光器的温度时，通过相位调制器调节波长锁定器的波长移动，将锁波信号的工作点调节至预设目标位置，此时工作点所对应的波长为可调激光器的工作波长，即将可调激光器的工作波长调节至预设目标波长。第一测温单元、第二测温单元和调温单元相互配合，能够实现可调激光器的波长调节和锁定的稳定性和准确性。
如图14所示，图14是本申请一个实施例提供的波长锁定方法的效果示意图。其中，实线曲线为可调激光器的锁波信号曲线，虚线曲线为可调激光器温度升高导致波长红移的锁波信号曲线，纵坐标为第二光电信号与第一光电信号的比值，其中预设目标位置为选定的波长锁定器的工作点，工作点对应的横坐标为目标波长，即可调激光器的所需工作波长。
结合图14，可以理解的是，在可调激光器工作在所需波长时，第一光电探测器和第二光电探测器分别接收来自光源模块的光，产生的第一光电信号和第二光电信号的比值为定值。将第二光电信号与第一光电信号的比值作为可调激光器工作波长的锁波信号，即可调激光器所在工作波长发生偏移，锁波信号随之变化，从而能够实现对可调激光器的波长特性进行监测。相位调制器设置在波长锁定器内环形波导绕线上，从而能够通过控制相位调制器调节环形波导绕线的温度，改变环形波导绕线的折射率，进而改变环形谐振腔的波长，改变锁波信号的工作点。当可调激光器工作在所需波长，通过相位控制器调节波长锁定器的波长移动，将锁波信号的工作点调节至预设目标位置，即锁波信号曲线峰值的一半，因为此处信号曲线变化幅度较大，具有更高的锁波精度。当可调激光器的工作波长发生偏移，则测得的第二光电信号与第一光电信号的比值偏离目标值，从而实现波长监测。第一测温单元监测波长锁定器的温度，随着相位调制器长时间的调节，波长锁定器芯片的温度不断升高，热量扩散到四周，甚至使得可调激光器的波长发生红移，因此，同时控制调温单元调节可调激光器的温度， 第二测温单元监测光源模块内的温度变化。因此，在相位调制器调节波长锁定器的相位时，可调激光器的调温单元调节整个系统温度，第一测温单元和第二测温单元分别监测波长锁定器和光源模块温度变化的情况下，可以监测可调激光器的波长变化并进行波长控制和稳定，从而实现波长锁定的功能。
本申请实施例包括：波长锁定器、可调激光器及波长锁定控制方法，波长锁定器应用于可调激光器，可调激光器设置有被设置为发出所需工作波长的光束的光源模块，该波长锁定器包括环形谐振腔、光输入端、第一光电探测器、第二光电探测器和相位调制器；光输入端设置有第一连接端和第二连接端，被设置为连接光源模块并接收来自光源模块的光束；环形谐振腔与第二连接端连接，被设置为产生梳状传输光谱，包括环形波导绕线，以及分别与环形波导绕线连接的第一分束器和第二分束器；第一光电探测器与第一连接端连接，被设置为接收来自光源模块光的一部分光以产生第一光电信号；第二光电探测器与第一分束器连接，被设置为接收经环形谐振腔滤波后的透射光以产生第二光电信号；相位调制器设置于环形波导绕线上，被设置为调节环形谐振腔的相位。根据本申请实施例提供的方案，光输入端能够接收来自于光源模块发出的光束，分成两部分；一部分光从第一连接端输出，第一光电探测器能够接收从第一连接端输出的光，产生第一光电信号；另一部分光从第二连接端输出，进入环形谐振腔，在第一分束器、第二分束器以及环形波导绕线的配合下谐振传输，产生梳状传输光谱。其中，经环形谐振腔滤波后的透射光被第二光电探测器接收，产生第二光电信号。从而，可以根据第一光电信号与第二光电信号得到可调激光器的锁波信号，并根据锁波信号变化获取可调激光器波长偏移情况，实现波长监测的功能；通过控制相位调制器以调节可调激光器的工作波长在预设目标波长，实现波长锁定的功能。因此，通过光输入端、环形谐振腔、相位调制器、第一光电探测器和第二光电探测器能够实现可调激光器的波长锁定器，无需采用外置体型标准具、光栅或滤波器阵列大型元件就能够实现可调激光器波长监测和调节稳定功能，降低对激光器件光源产生噪声干扰，提高调节精度，节省了波长锁定器的结构空间，降低封装工艺的复杂度，从而缩小可调激光器的尺寸，降低成本。
上面结合附图对本申请实施例作了详细说明，但是本申请不限于上述实施例，在技术领域普通技术人员所具备的知识范围内，还可以在不脱离本申请宗旨的前提下作出各种变化。

Claims (10)

  1. 一种波长锁定器，应用于可调激光器，所述可调激光器设置有被设置为发出具有所需工作波长光束的光源模块，所述波长锁定器包括：
    光输入端，被设置为连接所述光源模块并接收来自所述光源模块的光束，所述光输入端还设置有第一连接端和第二连接端；
    环形谐振腔，与所述第二连接端连接，所述环形谐振腔包括环形波导绕线，以及分别与所述环形波导绕线连接的第一分束器和第二分束器，所述环形波导绕线、所述第一分束器与所述第二分束器被设置为配合产生梳状传输光谱；
    第一光电探测器，与所述第一连接端连接，被设置为接收来自所述光源模块所发出的光的一部分光以产生第一光电信号；
    第二光电探测器，与所述第一分束器连接，被设置为接收经所述环形谐振腔滤波后的透射光以产生第二光电信号；
    相位调制器，设置于所述环形波导绕线上，被设置为调节所述环形谐振腔的相位。
  2. 根据权利要求1所述的波长锁定器，其中，所述波长锁定器内设置有第一测温单元，被设置为获取所述波长锁定器的第一温度数据。
  3. 根据权利要求1所述的波长锁定器，其中，所述波长锁定器集成于SOI芯片上。
  4. 根据权利要求1所述的波长锁定器，其中，所述光输入端包括如下类型中的一种：
    相耦合的第一反射镜和分束元件；
    相耦合的第二反射镜和第三反射镜；
    第四反射镜。
  5. 一种可调激光器，包括：权利要求1至4任意一项所述的波长锁定器；还包括被设置为发出光束的光源模块，所述光输入端连接所述光源模块并接收来自所述光源模块的具有所需工作波长的光束。
  6. 根据权利要求5所述的可调激光器，其中，所述可调激光器还包括被设置为调节所述可调激光器温度的调温单元和被设置为获取所述光源模块的第二温度数据的第二测温单元，所述调温单元与所述可调激光器连接，所述第二测温单元设置在所述光源模块上。
  7. 一种波长锁定控制方法，应用于可调激光器，所述可调激光器包括权利要求1至4任意一项所述的波长锁定器；还包括被设置为发出具有所需工作波长的光束的光源模块，所述光输入端连接所述光源模块并接收来自所述光源模块的光束；
    所述控制方法，包括：
    获取由所述第一光电探测器输出的第一光电信号和由所述第二光电探测器输出的第二光电信号；
    根据所述第一光电信号和所述第二光电信号得到锁波信号；
    根据所述锁波信号控制所述相位调制器将所述锁波信号的工作点调节至预设目标位置。
  8. 根据权利要求7所述的控制方法，其中，所述根据所述第一光电信号和所述第二光电 信号得到锁波信号，包括：
    根据所述第二光电信号与所述第一光信号的比值关系，得到锁波信号。
  9. 根据权利要求7所述的控制方法，其中，所述波长锁定器内设置有第一测温单元，被设置为获取所述波长锁定器的第一温度数据；
    所述根据所述锁波信号控制所述相位调制器将所述锁波信号的工作点调节至预设目标位置，包括：
    获取由所述第一测温单元输出的所述波长锁定器的第一温度数据；
    根据所述第一温度数据和所述锁波信号控制所述相位调制器将所述锁波信号的工作点调节至预设目标位置。
  10. 根据权利要求9所述的控制方法，其中，所述可调激光器还包括被设置为调节所述可调激光器温度的调温单元和被设置为获取所述光源模块的第二温度数据的第二测温单元，所述调温单元与所述可调激光器连接，所述第二测温单元设置在所述光源模块上；
    所述根据所述第一温度数据和所述锁波信号控制所述相位调制器将所述锁波信号的工作点调节至预设目标位置，包括：
    获取由所述第二测温单元输出的所述光源模块的第二温度数据；
    根据所述锁波信号、所述第一温度数据和所述第二温度数据，控制所述调温单元和所述相位调制器将所述可调激光器的工作波长调节至预设目标波长。
PCT/CN2022/106287 2021-09-13 2022-07-18 波长锁定器、可调激光器及波长锁定控制方法 WO2023035775A1 (zh)

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