Method and apparatus for wavelength locking of an external cavity laser

Abstract

The application discloses a wavelength locking method and device of an external cavity laser, and relates to the technical field of lasers.The wavelength locking method comprises the following steps: step S10, an initial driving current is applied to the laser to make the laser output laser, and a preset dither signal is applied to a piezoelectric inductor of the laser to make the cavity length of the laser produce dither; step S20, a dither response signal of the output laser under the cavity length dither is acquired; and step S30, the driving current is adjusted according to the dither response signal, so that the amplitude of the dither response signal reaches a minimum value, and wavelength locking is realized.The application can realize wavelength locking without using a table lookup method to determine the tuning parameters corresponding to the output frequency, can meet the long-term stable operation requirement of the laser, can reduce the data volume of the laser factory calibration, can simplify the calibration process, and is favorable for improving the calibration rate and productivity.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of laser, in particular to a wavelength locking method and device of an external cavity laser. BACKGROUND

[0002] Due to the rapid growth of bandwidth demand and network capacity, coherent optical communication network is about to enter the era of 400G or even 800G. As a light source, tunable narrow linewidth laser is the core device in the field of coherent optical communication. Facing the system of higher speed, the requirements of output power, linewidth and side mode suppression ratio of the laser are also improved accordingly. As a kind of light source with compact structure, long service life and good spectral characteristics, external cavity laser can realize wide range continuous tuning, and the linewidth can be less than 100 kHz, which has been widely used in the field of coherent optical communication.

[0003] In the external cavity semiconductor laser, the linewidth directly depends on the design length of the external cavity. Although the linewidth can be relatively small, the output laser will produce an uncertain phase shift due to external factors during use. The frequency point (center frequency) of the output laser still exists a certain frequency deviation. In long distance transmission, the frequency deviation will cause channel crosstalk and generate phase noise. Therefore, a wavelength locking device is needed in the external cavity laser to monitor, track and lock the output wavelength in real time to ensure the frequency stability of the output laser.

[0004] The current wavelength locking method is mostly based on the vernier caliper type bandpass filter unit of temperature tuning, which needs a large amount of calibration data to determine the relationship between the frequency point and the tuning parameters (such as angle, temperature, current, voltage value). In the working process, the lookup table method is used to determine the tuning parameters corresponding to the laser output frequency point and set the parameters. However, in actual work, the output frequency point will be affected by factors such as temperature, stress, aging and pump current. The precision and speed of the lookup table method are difficult to meet the long-term stable operation requirements of the laser. SUMMARY

[0005] The embodiment of the present application provides a wavelength locking device and method of an external cavity laser to solve the technical problem that the lookup table method is used to determine the tuning parameters corresponding to the laser output frequency point when the laser of the prior art performs wavelength locking, which is difficult to meet the long-term stable operation requirements of the laser.

[0006] In a first aspect, a wavelength locking method of an external cavity laser is provided, comprising the following steps:

[0007] An initial driving current is applied to the laser to make the laser output laser, and a preset dithering signal is applied to the piezoelectric sensor of the laser to make the cavity length of the laser dither;

[0008] A dithering response signal of the output laser under the dithering of the cavity length is acquired;

[0009] The driving current is adjusted according to the jitter response signal of the output laser under the cavity length jitter, so that the amplitude of the jitter response signal reaches a minimum value, and wavelength locking is achieved.

[0010] In some embodiments, the step of adjusting the driving current according to the jitter response signal so that the amplitude of the jitter response signal approaches a minimum value to achieve wavelength locking comprises:

[0011] determining whether the current amplitude of the jitter response signal is less than the previous amplitude;

[0012] if yes, increasing / decreasing the driving current by a preset step size, and then determining whether the next amplitude of the jitter response signal is less than the current amplitude;

[0013] if yes, continuing to increase / decrease the driving current by the preset step size, so that the amplitude of the jitter response signal continues to decrease, until the amplitude of the jitter response signal reaches a minimum value;

[0014] if no, decreasing / increasing the driving current by a preset step size, so that the amplitude of the jitter response signal decreases, until the amplitude of the jitter response signal reaches a minimum value.

[0015] In some embodiments, the step of adjusting the driving current according to the jitter response signal so that the amplitude of the jitter response signal reaches a minimum value to achieve wavelength locking further comprises:

[0016] operating the jitter response signal with two orthogonal reference signals to obtain the amplitude of the jitter response signal.

[0017] In some embodiments, the step of applying an initial driving current to the laser so that the laser outputs laser light comprises:

[0018] adjusting the parameters of the band-pass filter through preset calibration data, so that the output laser reaches a calibration frequency.

[0019] In some embodiments, the step of applying a preset jitter signal to the piezoelectric sensor of the laser to cause the cavity length of the laser to jitter comprises:

[0020] applying a sinusoidal or cosine voltage signal to the piezoelectric sensor of the laser.

[0021] In a second aspect, a wavelength locking device for an external cavity laser is provided, comprising: a controller and a piezoelectric sensor;

[0022] The piezoelectric sensor is arranged in the cavity of the laser and is electrically connected to the controller;

[0023] The controller comprises:

[0024] an application unit configured to apply an initial driving current to the laser to cause the laser to output laser light and apply a preset dithering signal to a piezoelectric sensor of the laser to cause the laser to dither a cavity length of the laser;

[0025] an acquisition unit configured to acquire a dithering response signal of the output laser light under the dithering of the cavity length;

[0026] a control unit configured to adjust the driving current according to the dithering response signal to cause an amplitude of the dithering response signal to reach a minimum value, thereby achieving wavelength locking.

[0027] In some embodiments, the control unit configured to adjust the driving current according to the dithering response signal to cause the amplitude of the dithering response signal to reach the minimum value, thereby achieving wavelength locking, includes:

[0028] determining whether a current amplitude of the dithering response signal is less than a previous amplitude;

[0029] if yes, increasing / decreasing the driving current by a preset step size and determining whether a next amplitude of the dithering response signal is less than the current amplitude;

[0030] if yes, continuing to increase / decrease the driving current by the preset step size to continue to decrease the amplitude of the dithering response signal until the amplitude of the dithering response signal reaches the minimum value;

[0031] if no, decreasing / increasing the driving current by the preset step size to decrease the amplitude of the dithering response signal until the amplitude of the dithering response signal reaches the minimum value.

[0032] In some embodiments, the control unit configured to adjust the driving current according to the dithering response signal to cause the amplitude of the dithering response signal to reach the minimum value, thereby achieving wavelength locking, further includes:

[0033] operating the dithering response signal with two orthogonal reference signals to obtain the amplitude of the dithering response signal.

[0034] In some embodiments, the wavelength locking device of the external cavity laser further includes:

[0035] a bandpass filter disposed in a cavity of the laser, the bandpass filter configured to adjust parameters of the bandpass filter by preset calibration data to cause the output laser light to reach a calibration frequency.

[0036] In some embodiments, the wavelength locking device of the external cavity laser further includes:

[0037] a beamsplitter, a photoelectric converter, and a transimpedance amplifier;

[0038] the beamsplitter configured to split a portion of the output laser light to the photoelectric converter;

[0039] The photoelectric converter is electrically connected with the transimpedance amplifier, and is configured to convert the optical signal of the output laser under the cavity length dithering into an electrical signal and output to the transimpedance amplifier.

[0040] The transimpedance amplifier is electrically connected with the controller, and is configured to amplify the electrical signal converted by the photoelectric converter and output to the controller.

[0041] The technical scheme provided by the present application has the following beneficial effects:

[0042] The wavelength locking method and device of the external cavity laser provided by the embodiment of the present application first apply an initial driving current to the laser to make the laser output laser, and apply a preset dithering signal to the piezoelectric sensor of the laser to make the cavity length of the laser dither; then acquire a dithering response signal of the output laser under the cavity length dithering; finally, adjust the driving current according to the dithering response signal to make the amplitude of the dithering response signal reach a minimum value, and realize wavelength locking. When the wavelength is locked, the frequency of the output laser is uniform and stable. The present application can realize wavelength locking without using the table lookup method to determine the tuning parameter corresponding to the output frequency point, can meet the long-term stable operation requirement of the laser, can also reduce the data amount of the laser factory calibration, simplify the calibration process, and is conducive to improving the calibration rate and productivity. BRIEF DESCRIPTION OF DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0044] Figure 1 The flowchart of the wavelength locking method of the external cavity laser provided by the embodiment of the present application;

[0045] Figure 2 The flowchart of the step S30 in the embodiment of the present application; Figure 1

[0046] Figure 3 The structure schematic diagram of the wavelength locking device of the external cavity laser provided by the embodiment of the present application;

[0047] Figure 4 The structure schematic diagram of the controller provided by the embodiment of the present application;

[0048] Figure 5 The schematic diagram of the output laser of the external cavity laser before wavelength locking provided by the embodiment of the present application;

[0049] Figure 6 ​A schematic view of output laser of the external cavity laser after wavelength locking is provided for the embodiment of the present application.

[0050] In the figure:

[0051] 1, cavity;

[0052] 2, controller;

[0053] 3, laser gain chip;

[0054] 4, phase tuner;

[0055] 5, piezoelectric sensor;

[0056] 6, beamsplitter;

[0057] 7, photoelectric converter;

[0058] 8, transimpedance amplifier;

[0059] 9, band-pass filter;

[0060] 10, current driver. DETAILED DESCRIPTION

[0061] In order to make the purpose, technical scheme and advantages of the embodiment of the present application more clear, the technical scheme of the embodiment of the present application will be described clearly and completely below with reference to the drawings in the embodiment of the present application. Obviously, the described embodiment is a part of the embodiment of the present application, rather than all the embodiments. Based on the embodiment in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0062] The embodiment of the present application provides a wavelength locking method of an external cavity laser, which can solve the technical problem that when the laser in the prior art is wavelength-locked, the lookup table method is used to determine the tuning parameter corresponding to the laser output frequency point, and it is difficult to meet the long-term stable operation requirement of the laser.

[0063] Referring to Figure 1 The embodiment of the present application provides a wavelength locking method of an external cavity laser, which comprises the following steps:

[0064] Step S10, an initial driving current is applied to the laser to make the laser output laser, and a preset dithering signal is applied to the piezoelectric sensor of the laser to make the cavity length of the laser dither.

[0065] Referring to Figure 3As shown in the figure, the external cavity laser generally is provided with a cavity 1 and a controller 2, and a laser gain chip 3 and a phase tuner 4 are sequentially arranged in the cavity 1. When the laser is started, the controller 2 outputs an initial driving current to the phase tuner 4 through a current driver 10, and the phase tuner 4 outputs laser at the rear end. The application further increases a piezoelectric sensor 5 at the rear end of the phase tuner 4, and the piezoelectric sensor 5 is electrically connected with the controller 2. The controller 2 applies a preset dithering signal to the piezoelectric sensor 5, so that the cavity length of the laser is dithered. Figure 3 As shown in the figure, for the convenience of understanding, the distance between the right side of the laser gain chip 3 and the left side of the piezoelectric sensor 5 can be regarded as the cavity length. When the controller 2 applies the preset dithering signal to the piezoelectric sensor 5, the piezoelectric sensor 5 is correspondingly deformed, and then the cavity length is also correspondingly dithered. The dithering of the cavity length is equivalent to applying a certain phase shift dithering to the output laser. Alternatively, a sinusoidal or cosine voltage signal is applied to the piezoelectric sensor 5 of the laser. The sinusoidal or cosine voltage signal is easy to generate and is convenient for subsequent calculation and control (usually a sinusoidal or cosine voltage signal with a low frequency, generally in the range of 100-1 kHz, depending on the cavity length and the size of the piezoelectric sensor). The controller 2 is provided with a digital-to-analog converter DAC1, and the digital-to-analog converter DAC1 applies the sinusoidal or cosine voltage signal to the piezoelectric sensor 5. The controller 2 is provided with a digital-to-analog converter DAC2, and the digital-to-analog converter DAC2 outputs a control signal to the current driver 10, so that the current driver 10 outputs a driving current to the phase tuner 4. The controller 2 can adjust the driving current through the digital-to-analog converter DAC2.

[0066] In step S20, the dithering response signal of the output laser under the cavity length dithering is acquired.

[0067] As shown in the figure, the external cavity laser generally is provided with a cavity 1 and a controller 2, and a laser gain chip 3 and a phase tuner 4 are sequentially arranged in the cavity 1. When the laser is started, the controller 2 outputs an initial driving current to the phase tuner 4 through a current driver 10, and the phase tuner 4 outputs laser at the rear end. The application further increases a piezoelectric sensor 5 at the rear end of the phase tuner 4, and the piezoelectric sensor 5 is electrically connected with the controller 2. The controller 2 applies a preset dithering signal to the piezoelectric sensor 5, so that the cavity length of the laser is dithered. Figure 3 As shown in the figure, the external cavity laser generally is provided with a cavity 1 and a controller 2, and a laser gain chip 3 and a phase tuner 4 are sequentially arranged in the cavity 1. When the laser is started, the controller 2 outputs an initial driving current to the phase tuner 4 through a current driver 10, and the phase tuner 4 outputs laser at the rear end. The application further increases a piezoelectric sensor 5 at the rear end of the phase tuner 4, and the piezoelectric sensor 5 is electrically connected with the controller 2. The controller 2 applies a preset dithering signal to the piezoelectric sensor 5, so that the cavity length of the laser is dithered.

[0068] When the laser is in use, the output laser will have an uncertain phase shift due to external factors, and the expression of the output laser is as follows: Pout = cos (ωt + θ), wherein θ is the phase shift amount, and ω is the center frequency of the output laser. A preset dither signal Acos (ω1t) is applied, wherein A is the amplitude of the preset dither signal, and ω1 is the frequency of the preset dither signal. When the preset dither signal is superimposed on the output laser with the uncertain phase shift, the output laser passes through the beam splitter 6, the photoelectric converter 7 and the transimpedance amplifier 8, and finally the dither response signal obtained by the controller 2 is: Vout = Acos (ωt)cos (ω1t)sinθ.

[0069] In step S30, the driving current is adjusted according to the dither response signal, so that the amplitude of the dither response signal reaches the minimum value, and the wavelength locking is realized.

[0070] As can be known from the foregoing analysis, in an ideal case, assuming that the phase shift θ = 0, at this time the output laser Pout = cos (ωt) does not need external control, and the wavelength of the output laser is in a locked state. However, in a real case, the laser is in use, and the output laser will have an uncertain phase shift due to external factors, that is, the phase shift θ is not zero, and the frequency (the center frequency of the laser) of the output laser will have a certain frequency offset, as shown in FIG. 2. Therefore, a certain phase shift dither (cavity length dither) is generated in the application, which is superimposed with the uncertain phase shift of the laser, and the phase of the output laser is finely adjusted by adjusting the driving current on the phase tuner 4, so that the amplitude of the final dither response signal Vout of the output laser is minimized, that is, the output laser after superimposed with the cavity length dither realizes the wavelength locking, as shown in FIG. 3. Figure 5 Figure 6

[0071] The wavelength locking method of the external cavity laser in the embodiment of the application first applies an initial driving current to the laser to make the laser output laser, and applies a preset dither signal to the piezoelectric inductor of the laser to make the cavity length of the laser have a dither; then acquires the dither response signal of the output laser under the cavity length dither; and finally adjusts the driving current according to the dither response signal, so that the amplitude of the dither response signal reaches the minimum value, and the wavelength locking is realized. When the wavelength is locked, the frequency of the output laser is uniformly stable. The wavelength locking can be realized without using the table lookup method to determine the tuning parameters corresponding to the output frequency, which can meet the long-term stable operation requirement of the laser, can reduce the data amount of the laser factory calibration, can simplify the calibration process, and is beneficial to improve the calibration rate and the production capacity.

[0072] As an optional implementation, in one embodiment of the application, as shown in FIG. 4, the step of adjusting the driving current according to the dither response signal, so that the amplitude of the dither response signal approaches the minimum value, and the wavelength locking is realized, includes: Figure 2

[0073] ​​​Step S301, judging whether the current amplitude of the dithering response signal is less than the last amplitude;

[0074] Step S302, if yes, increasing / decreasing the driving current by a preset step, and judging whether the next amplitude of the dithering response signal is less than the current amplitude again:

[0075] Step S303, if yes, continuing to increase / decrease the driving current by the preset step, so as to continue to decrease the amplitude of the dithering response signal, until the amplitude of the dithering response signal reaches the minimum value;

[0076] Step S304, if no, decreasing / increasing the driving current by the preset step, so as to decrease the amplitude of the dithering response signal, until the amplitude of the dithering response signal reaches the minimum value.

[0077] For example, the initial driving current is assumed to be 100 mA, and the amplitude of the dithering signal is always 80 mV. Due to the change of the external environment, the current amplitude of the dithering signal becomes 75 mV at a certain moment. At this moment, the driving current can be increased by a preset step (2 mA), and it is judged whether the next amplitude of the dithering signal is less than the current amplitude again:

[0078] If the next amplitude is 72 mV, the driving current is continued to be increased by the preset step, so as to continue to decrease the amplitude of the dithering signal. If the last amplitude of the dithering signal is 70 mV, and the current amplitude is 71 mV, the driving current corresponding to the minimum amplitude (70 mV) of the dithering signal is taken as the driving current of the phase tuner 4.

[0079] If the next amplitude is 78 mV, the driving current is decreased by the preset step, so as to continue to decrease the amplitude of the dithering signal. If the last amplitude of the dithering signal is 72 mV, and the current amplitude is 73 mV, the driving current corresponding to the minimum amplitude (72 mV) of the dithering signal is taken as the driving current of the phase tuner 4. In addition, the control logic of adjusting the driving current by first decreasing the driving current is similar to the above, and is not described herein.

[0080] The above operation logic can quickly realize the wavelength locking of the laser during long-term use, and improve the long-term stability of the laser.

[0081] As an optional implementation, in one embodiment of the application, the step of adjusting the driving current according to the dithering response signal, so as to make the amplitude of the dithering response signal reach the minimum value, and realize the wavelength locking, further comprises:

[0082] The dithering response signal is operated with two orthogonal reference signals to obtain the amplitude of the dithering response signal.

[0083] Specifically, two orthogonal reference signals Ref0=V ref cosf, Ref90 = V ref sinf, two orthogonal reference signals are multiplied by the jitter response signal Vout, respectively, to obtain: V1 = VoutV ref cosf, V2 = VoutV ref sinf, then the amplitude of the jitter response signal satisfies: A 2 = V1 2 + V2 2 / V ref 2 The amplitude of the obtained jitter response signal is accurate and reliable.

[0084] As an optional implementation, in an embodiment of the application, the step of applying an initial driving current to the laser to make the laser output laser light comprises:

[0085] The parameters of the band-pass filter are adjusted by the preset calibration data to make the output laser reach the calibration frequency, so that the wavelength locking efficiency of the laser is improved.

[0086] Referring to FIGS. 1 and 2, Figure 3 and Figure 4 the embodiment of the application further provides a wavelength locking device of an external cavity laser, comprising a controller 2 and a piezoelectric inductor 5.

[0087] The piezoelectric inductor 5 is arranged in a cavity 1 of the laser and is electrically connected to the controller 2.

[0088] The controller 2 comprises an applying unit, an obtaining unit and a control unit.

[0089] The applying unit is used for applying an initial driving current to the laser to make the laser output laser light, and applying a preset jitter signal to the piezoelectric inductor of the laser to make the cavity length of the laser jitter.

[0090] The obtaining unit is used for obtaining a jitter response signal of the output laser under the jitter of the cavity length.

[0091] The control unit is used for adjusting the driving current according to the jitter response signal to make the amplitude of the jitter response signal reach a minimum value, so as to realize wavelength locking.

[0092] As an optional implementation, in an embodiment of the application, the control unit is used for adjusting the driving current according to the jitter response signal to make the amplitude of the jitter response signal reach a minimum value, so as to realize wavelength locking, which comprises:

[0093] determining whether a current amplitude of the jitter response signal is smaller than a last amplitude;

[0094] If yes, increasing / decreasing the driving current by a preset step, and determining whether a next amplitude of the jitter response signal is smaller than the current amplitude again.

[0095] If yes, continue to increase / decrease the driving current by a preset step size, and continue to decrease the amplitude of the dithering response signal until the amplitude of the dithering response signal reaches a minimum value; if no, decrease / increase the driving current by a preset step size, and decrease the amplitude of the dithering response signal until the amplitude of the dithering response signal reaches a minimum value.

[0096] As an optional implementation, in one embodiment of the application, the control unit is configured to adjust the driving current according to the dithering response signal so that the amplitude of the dithering response signal reaches a minimum value, and achieve wavelength locking, and further comprising:

[0097] The amplitude of the dithering response signal is obtained by operating the dithering response signal with two orthogonal reference signals.

[0098] As an optional implementation, in one embodiment of the application, the wavelength locking device of the external cavity laser further comprises a band-pass filter 9, which is arranged in the cavity 1 of the laser, and is generally arranged at the rear end of the laser gain chip 3. The parameters of the band-pass filter 9 are adjusted by preset calibration data so that the output laser reaches a calibration frequency. The band-pass filter 9 can be two temperature-controlled optical filters.

[0099] As an optional implementation, in one embodiment of the application, the wavelength locking device of the external cavity laser further comprises a beam splitter 6, a photoelectric converter 7, and a transimpedance amplifier 8.

[0100] The beam splitter 6 is configured to split a part of the output laser to the photoelectric converter 7. The photoelectric converter 7 is electrically connected to the transimpedance amplifier 8. The photoelectric converter 7 is configured to convert the optical signal of the output laser under the cavity length dithering into an electrical signal and output the electrical signal to the transimpedance amplifier 8. The transimpedance amplifier 8 is electrically connected to the controller 2. The transimpedance amplifier 8 is configured to amplify the electrical signal converted by the photoelectric converter 7 and output the electrical signal to the controller 2. The photoelectric converter 7 can be a photodiode.

[0101] As an optional implementation, in one embodiment of the application, the piezoelectric sensor 5 can be a piezoelectric ceramic (PZT) with inverse piezoelectric effect. The piezoelectric ceramic has nanoscale micro-deformation and microsecond-level response speed, which not only improves the output wavelength accuracy of the external cavity laser, but also greatly improves the locking speed and shortens the laser initialization and wave cutting time.

[0102] In the description of the present application, it should be noted that the terms "upper", "lower", and the like are used for indicating the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. Unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting" should be understood broadly, for example, can be fixed connection, can also be detachable connection, or integral connection; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0103] It should be noted that in the present application, relational terms such as "first" and "second", and the like are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus including a series of elements includes not only those elements, but also other elements not explicitly listed, or other elements inherent in such a process, method, article or apparatus. Without more limitations, the element defined by the statement "comprising a" does not exclude the presence of additional identical elements in the process, method, article or apparatus including the element.

[0104] The above is only a specific embodiment of the present application, enabling those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features of the present application.

Claims

1. A wavelength locking method for an external cavity laser, characterized in that, Includes the following steps: An initial driving current is applied to the laser to make the laser output laser light, and a preset jitter signal is applied to the piezoelectric sensor of the laser to make the cavity length of the laser jitter. Acquire the jitter response signal of the output laser under cavity length jitter; The drive current is adjusted according to the jitter response signal of the output laser under cavity length jitter, so that the amplitude of the jitter response signal reaches the minimum value, thereby achieving wavelength locking. The step of adjusting the drive current according to the jitter response signal to minimize the amplitude of the jitter response signal and achieve wavelength locking further includes: The amplitude of the jitter response signal is obtained by performing calculations on the jitter response signal and two orthogonal reference signals. Specifically, the two orthogonal reference signals are: Ref 0= V ref cos f , Ref 90 = V ref sin f The two orthogonal reference signals and the jitter response signal are combined. After multiplying them separately, we get: V1 = VoutV ref cos f , V2 = VoutV ref sin f Then the amplitude of the jitter response signal satisfies: A 2 = V1 2 + V2 2 / V ref 2 .

2. The wavelength locking method for an external cavity laser according to claim 1, characterized in that, The step of adjusting the drive current according to the jitter response signal to make the amplitude of the jitter response signal approach the minimum value, thereby achieving wavelength locking, includes: Determine whether the current amplitude of the jitter response signal is less than the previous amplitude; If so, increase / decrease the drive current by a preset step size, and then determine whether the next amplitude of the jitter response signal is less than the current amplitude: If so, continue to increase / decrease the drive current by a preset step size to further reduce the amplitude of the jitter response signal until the amplitude of the jitter response signal reaches its minimum value; If not, decrease / increase the drive current by a preset step size to reduce the amplitude of the jitter response signal until the amplitude of the jitter response signal reaches its minimum value.

3. The wavelength locking method for an external cavity laser according to claim 1, characterized in that, The step of applying an initial driving current to the laser to cause the laser to output laser light includes: By adjusting the parameters of the bandpass filter using preset calibration data, the output laser can reach the calibrated frequency.

4. The wavelength locking method for an external cavity laser according to claim 1, characterized in that, The step of applying a preset jitter signal to the piezoelectric sensor of the laser to cause jitter in the cavity length of the laser includes: A sinusoidal or cosine voltage signal is applied to the piezoelectric sensor of the laser.

5. A wavelength locking device for an external cavity laser, characterized in that, include: Controller (2) and piezoelectric sensor (5); The piezoelectric sensor (5) is located inside the cavity (1) of the laser and is electrically connected to the controller (2); The controller (2) includes: An application unit is used to apply an initial driving current to the laser to make the laser output laser light, and to apply a preset jitter signal to the piezoelectric sensor of the laser to make the cavity length of the laser jitter. The acquisition unit is used to acquire the jitter response signal of the output laser under cavity length jitter; The control unit is used to adjust the drive current according to the jitter response signal so that the amplitude of the jitter response signal reaches the minimum value, thereby achieving wavelength locking; The step of adjusting the drive current according to the jitter response signal to minimize the amplitude of the jitter response signal and achieve wavelength locking also includes: The amplitude of the jitter response signal is obtained by performing calculations on the jitter response signal and two orthogonal reference signals. Specifically, the two orthogonal reference signals are: Ref 0= V ref cos f , Ref 90 = V ref sin f The two orthogonal reference signals and the jitter response signal are combined. After multiplying them separately, we get: V1 = VoutV ref cos f , V2 = VoutV ref sin f Then the amplitude of the jitter response signal satisfies: A 2 = V1 2 + V2 2 / V ref 2 .

6. The wavelength locking device for an external cavity laser according to claim 5, characterized in that, The control unit is used to adjust the drive current according to the jitter response signal to minimize the amplitude of the jitter response signal and achieve wavelength locking, including: Determine whether the current amplitude of the jitter response signal is less than the previous amplitude; If so, increase / decrease the drive current by a preset step size, and then determine whether the next amplitude of the jitter response signal is less than the current amplitude: If so, continue to increase / decrease the drive current by a preset step size to further reduce the amplitude of the jitter response signal until the amplitude of the jitter response signal reaches its minimum value; If not, decrease / increase the drive current by a preset step size to reduce the amplitude of the jitter response signal until the amplitude of the jitter response signal reaches its minimum value.

7. The wavelength locking device for an external cavity laser according to claim 5, characterized in that, Also includes: A bandpass filter (9) is installed inside the cavity (1) of the laser. The parameters of the bandpass filter (9) are adjusted by preset calibration data so that the output laser reaches the calibration frequency.

8. The wavelength locking device for an external cavity laser according to claim 5, characterized in that, Also includes: Beam splitter (6), photoelectric converter (7), and transimpedance amplifier (8); The beam splitter (6) is used to send the split portion of the output laser to the photoelectric converter (7); The photoelectric converter (7) is electrically connected to the transimpedance amplifier (8). The photoelectric converter (7) is used to convert the optical signal of the output laser under cavity length jitter into an electrical signal and output it to the transimpedance amplifier (8). The transimpedance amplifier (8) is electrically connected to the controller (2). The transimpedance amplifier (8) is used to amplify the electrical signal converted by the photoelectric converter (7) and output it to the controller (2).

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