Semiconductor high-speed laser wavelength tuning method
By dividing the wavelength tuning area in semiconductor high-speed lasers and establishing a current control model, the problem of insufficient distinction between tuning mechanisms in traditional methods is solved, and fine adjustment of wavelengths and stability improvement is achieved to meet various application needs.
Patent Information
- Application Number
- CN202411417629.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-11
- Publication Date
- 2025-01-03
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
The traditional semiconductor high-speed laser wavelength tuning method fails to clearly distinguish different tuning mechanisms, resulting in performance not reaching the best state, and ignores wavelength detuning and optical loss caused by interference factors, affecting tuning accuracy and stability.
By determining the target wavelength range, dividing the laser wavelength tuning area into the active area and the grating area, controlling the area in a divided region based on the laser signal monitoring results, establishing a current control model for the active area and the grating area, and performing current on wavelengths that do not meet the monitoring threshold. Tune to achieve fine adjustment of wavelength.
It achieves a wide range of wavelength coverage and continuous wavelength adjustable, meets different application needs, improves tuning accuracy and stability, and has high sensitivity and high accuracy.
Smart Images
Figure CN119253402A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of semiconductor materials, and more specifically to a wavelength tuning method for a semiconductor high-speed laser. Background Art
[0002] Semiconductor materials are the core foundation for wavelength tuning of semiconductor high-speed lasers. With the advancement of materials science, researchers are constantly optimizing the composition and structure of semiconductor materials to improve their optoelectronic properties. In particular, for the needs of high-speed lasers, the selection of materials needs to meet the requirements of high carrier mobility, low absorption loss, and good thermal stability. At the same time, the application of nanostructures such as quantum wells and quantum dots enables semiconductor lasers to achieve finer wavelength tuning on a smaller scale.
[0003] At present, the mainstream wavelength tuning mechanisms include carrier injection tuning, thermal tuning and mechanical tuning. Carrier injection tuning achieves wavelength tuning by changing the current in the laser; thermal tuning changes the refractive index by changing the temperature of the laser, thereby achieving wavelength tuning; mechanical tuning is based on micro-electromechanical system technology and achieves wavelength selection by moving components such as mirrors or gratings.
[0004] However, traditional methods may not clearly distinguish different tuning mechanisms. This lack of distinction leads to mutual influence and constraints between different mechanisms in practical applications, which may make the overall performance not reach the optimal state. In addition, the wavelength detuning and optical loss caused by interference factors are ignored during the wavelength tuning process, thereby affecting the tuning accuracy and stability. Summary of the invention
[0005] In order to overcome the above defects of the prior art, the present invention provides a method for tuning the wavelength of a semiconductor high-speed laser to solve the problems existing in the above background technology.
[0006] The present invention provides the following technical solution: a method for tuning the wavelength of a semiconductor high-speed laser, comprising the following steps: Step S01: Determine a target wavelength range: determine a target wavelength range according to different types of semiconductor high-speed lasers, and set the target wavelength range as a monitoring threshold for wavelength monitoring; Step S02: wavelength monitoring of the semiconductor high-speed laser: the laser detector receives the laser signal emitted by the semiconductor high-speed laser, monitors the wavelength of the laser signal, and determines whether the wavelength meets the monitoring threshold; Step S03: Laser wavelength tuning region division: the laser wavelength tuning region is divided into an active region and a grating region, and the wavelength is controlled in different regions according to the monitoring result of the wavelength monitoring of the laser signal emitted by the semiconductor high-speed laser; Step S04: Active area current control of the wavelength: an active area wavelength control model is established according to the regional control result in step S03, and wavelength tuning is performed based on active area current control for wavelengths that do not meet the monitoring threshold; Step S05: performing grating area current control on the wavelength: establishing a grating area wavelength control model according to the regional control result in step S03, and performing wavelength tuning based on the grating area current control on the wavelength that does not meet the monitoring threshold; Step S06: Outputting wavelength information after regional control: outputting the wavelength information of active area current control in step S04 and the wavelength information of grating area current control in step S05 to the monitoring background; Step S07: receiving the wavelength information after the regional control: receiving the wavelength information after the regional control output in step S06, comparing the wavelength information with the monitoring threshold in step S01, and completing the wavelength tuning of the semiconductor high-speed laser.
[0007] Preferably, in step S01, the maximum value of the target wavelength range corresponds to the maximum value of the monitoring threshold, and the minimum value of the target wavelength range corresponds to the minimum value of the monitoring threshold.
[0008] Preferably, in step S02, the laser detector receives a laser signal emitted by a semiconductor high-speed laser, and compares the wavelength value of the laser signal with the monitoring threshold of the wavelength monitoring set in step S01. If the wavelength value of the laser signal is within the monitoring threshold range, it is judged that the wavelength value of the laser signal meets the monitoring threshold; if the wavelength value of the laser signal is not within the monitoring threshold range, it is judged that the wavelength value of the laser signal does not meet the monitoring threshold, and the laser is wavelength tuned according to the wavelength value of the laser signal.
[0009] Preferably, in step S03, the laser wavelength tuning region is divided into an active region and a grating region. If the wavelength value of the laser signal is less than the minimum value of the monitoring threshold, the wavelength value of the laser signal is current-controlled in the active region. If the wavelength value of the laser signal is greater than the maximum value of the monitoring threshold, the wavelength value of the laser signal is current-controlled in the grating region.
[0010] Preferably, if the wavelength value of the laser signal is less than the minimum value of the monitoring threshold, the content of the active area current control of the wavelength value of the laser signal is: establishing an active area wavelength control model, and performing wavelength tuning based on the active area current control for the wavelength that does not meet the monitoring threshold, the specific content is as follows: Step S1: Calculate the optical field gain for the wavelength that does not meet the monitoring threshold. The calculation formula is: ,in represents the light field gain value, represents the gain factor, represents the carrier density, represents the transparent carrier concentration, represents the gain compression constant, represents the photon number density; Step S2: Calculate the detuning coefficient for the wavelength that does not meet the monitoring threshold. The calculation formula is: ,in represents the detuning coefficient, represents the light field limitation factor, represents the line width enhancement factor, represents the differential gain; Step S3: Establish an active region wavelength control model to calculate the carrier wavelength tuning rate, and the calculation formula is: ,in represents the carrier wavelength tuning rate, represents the current injection efficiency, Indicates the injected current value, represents the width of the waveguide, represents the thickness of the waveguide, s represents the carrier lifetime, represents the group velocity of the light field wave packet; Step S4: When the carrier wavelength tuning rate meets the preset rate threshold range, the injection of current is stopped to complete the active region current control.
[0011] Preferably, if the wavelength value of the laser signal is greater than the maximum value of the monitoring threshold, the content of the grating area current control of the wavelength value of the laser signal is: establishing a grating area wavelength control model, and performing wavelength tuning based on the grating area current control for the wavelength that does not meet the monitoring threshold, the specific content is as follows: Step S1: Calculate the change in effective refractive index caused by the injected current. The calculation formula is: ,in represents the change in effective refractive index caused by the injected current, represents a constant, is the wavelength of the incident light, is the speed of light in vacuum, is the effective refractive index, represents a constant, represents the electron density, represents the hole density, represents the effective mass of the electron, represents the effective mass of the hole; Step S2: The change in the effective refractive index in step S1 generates additional optical loss. The calculation formula of the absorption coefficient of the optical loss is: ,in The absorption coefficient representing the optical loss, is the mobility of electrons, represents the mobility of holes; Step S3: When the change in the effective refractive index caused by the injected current meets the preset threshold range of the effective refractive index change, and the additional optical loss generated by the change in the effective refractive index meets the preset threshold range of the optical loss change, stop injecting current to complete the grating area current control.
[0012] Preferably, in step S06, when the wavelength information of the active area current control in step S04 and the wavelength information of the grating area current control in step S05 are output to the monitoring background, the wavelength information is combined and processed by using a digital filter.
[0013] Preferably, in step S07, the wavelength information after regional control output in step S06 is received, and the wavelength information is compared with the monitoring threshold in step S01. If the wavelength information after regional control output meets the monitoring threshold in step S01, the wavelength tuning of the semiconductor high-speed laser is completed. If the wavelength information after regional control output does not meet the monitoring threshold in step S01, the process returns to step S03 to perform regional control on the wavelength again.
[0014] Technical effects and advantages of the present invention: The present invention is provided with step S01: determining a target wavelength range, step S02: performing wavelength monitoring on a semiconductor high-speed laser, step S03: dividing the laser wavelength tuning region, step S04: performing active region current control on the wavelength, step S05: performing grating region current control on the wavelength, step S06: outputting wavelength information after regional control, step S07: receiving wavelength information after regional control, performing regional control on the wavelength according to a monitoring result of wavelength monitoring on a laser signal emitted by the semiconductor high-speed laser, establishing an active region wavelength control model and a grating region wavelength control model, performing wavelength tuning based on active region current control on wavelengths that do not meet a monitoring threshold, achieving a wide wavelength coverage range, and achieving continuous wavelength adjustability within a certain range, thereby meeting the needs of different applications. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 The present invention is a flow chart of a method for wavelength tuning of a semiconductor high-speed laser. DETAILED DESCRIPTION
[0016] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the present invention. In addition, the forms of the various structures recorded in the following embodiments are only examples. The wavelength tuning method of a semiconductor high-speed laser involved in the present invention is not limited to the various structures recorded in the following embodiments. All other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention.
[0017] like Figure 1 As shown, the present invention provides a method for tuning the wavelength of a semiconductor high-speed laser, comprising the following steps: Step S01: Determine a target wavelength range: determine a target wavelength range according to different types of semiconductor high-speed lasers, and set the target wavelength range as a monitoring threshold for wavelength monitoring; Step S02: wavelength monitoring of the semiconductor high-speed laser: the laser detector receives the laser signal emitted by the semiconductor high-speed laser, monitors the wavelength of the laser signal, and determines whether the wavelength meets the monitoring threshold; Step S03: Laser wavelength tuning region division: the laser wavelength tuning region is divided into an active region and a grating region, and the wavelength is controlled in different regions according to the monitoring result of the wavelength monitoring of the laser signal emitted by the semiconductor high-speed laser; Step S04: Active area current control of the wavelength: an active area wavelength control model is established according to the regional control result in step S03, and wavelength tuning is performed based on active area current control for wavelengths that do not meet the monitoring threshold; Step S05: performing grating area current control on the wavelength: establishing a grating area wavelength control model according to the regional control result in step S03, and performing wavelength tuning based on the grating area current control on the wavelength that does not meet the monitoring threshold; Step S06: Outputting wavelength information after regional control: outputting the wavelength information of active area current control in step S04 and the wavelength information of grating area current control in step S05 to the monitoring background; Step S07: receiving the wavelength information after the regional control: receiving the wavelength information after the regional control output in step S06, comparing the wavelength information with the monitoring threshold in step S01, and completing the wavelength tuning of the semiconductor high-speed laser.
[0018] In this embodiment, it should be specifically explained that in step S01, the semiconductor high-speed laser Based on the third-generation semiconductor materials, an energy band structure with characteristics such as quantum wells, quantum wires, and quantum dots is formed to achieve population inversion and optical gain, including ultrafast lasers and superluminescent tubes. Ultrafast lasers use third-generation semiconductor materials to achieve mode locking in semiconductor lasers, generate picosecond pulses, and achieve corresponding functions. Superluminescent tubes use special structures created based on third-generation semiconductor materials to increase the coherence length of spontaneous radiation, producing a wider spectrum width and higher directionality than ordinary LEDs. The maximum value of the target wavelength range corresponds to the maximum value of the monitoring threshold, and the minimum value of the target wavelength range corresponds to the minimum value of the monitoring threshold.
[0019] In the present embodiment, it should be specifically explained that in step S02, the laser detector receives the laser signal emitted by the semiconductor high-speed laser, and compares the wavelength value of the laser signal with the monitoring threshold of the wavelength monitoring set in step S01. If the wavelength value of the laser signal is within the monitoring threshold range, it is judged that the wavelength value of the laser signal meets the monitoring threshold. If the wavelength value of the laser signal is not within the monitoring threshold range, it is judged that the wavelength value of the laser signal does not meet the monitoring threshold, and the laser is wavelength tuned according to the wavelength value of the laser signal. Special center wavelength, power, and spectral width products can be customized according to user needs.
[0020] In this embodiment, it should be specifically explained that in step S03, the laser wavelength tuning area is divided into an active area and a grating area. If the wavelength value of the laser signal is less than the minimum value of the monitoring threshold, the wavelength value of the laser signal is controlled by the active area current. If the wavelength value of the laser signal is greater than the maximum value of the monitoring threshold, the wavelength value of the laser signal is controlled by the grating area current. The active region is the core area of the laser that generates optical gain and is responsible for providing light amplification and radiation. When current is injected into the active region, the carriers therein recombine and release photons, forming spontaneous radiation and stimulated radiation of light. In the active region, the output optical power and wavelength of the laser can be initially regulated by precisely controlling the size and change of the injected current. The grating region is mainly used to achieve precise tuning and selection of the wavelength. By etching or growing a specific grating structure in the grating region, light of a specific wavelength can be reflected or transmitted, thereby achieving wavelength selection and tuning. The existence of the grating region enables the laser to continuously or discretely tune its output wavelength within a certain range to meet different application requirements.
[0021] In this embodiment, it should be specifically explained that if the wavelength value of the laser signal is less than the minimum value of the monitoring threshold, the content of the active area current control of the wavelength value of the laser signal is: establishing an active area wavelength control model, and performing wavelength tuning based on the active area current control for the wavelength that does not meet the monitoring threshold. The specific content is as follows: Step S1: Calculate the optical field gain for the wavelength that does not meet the monitoring threshold. The calculation formula is: ,in represents the light field gain value, represents the gain factor, represents the carrier density, represents the transparent carrier concentration, represents the gain compression constant, represents the photon number density; Step S2: Calculate the detuning coefficient for the wavelength that does not meet the monitoring threshold. The calculation formula is: ,in represents the detuning coefficient, represents the light field limitation factor, represents the line width enhancement factor, represents the differential gain, represents the carrier density; Step S3: Establish an active region wavelength control model to calculate the carrier wavelength tuning rate, and the calculation formula is: ,in represents the carrier wavelength tuning rate, represents the current injection efficiency, Indicates the injected current value, represents the width of the waveguide, represents the thickness of the waveguide, s represents the carrier lifetime, represents the group velocity of the light field wave packet, represents the detuning coefficient, represents the carrier density, represents the light field gain value, represents the photon number density; Step S4: When the carrier wavelength tuning rate meets the preset rate threshold range, the injection of current is stopped to complete the active region current control.
[0022] In this embodiment, it should be specifically explained that if the wavelength value of the laser signal is greater than the maximum value of the monitoring threshold, the content of the grating area current control of the wavelength value of the laser signal is: establish a grating area wavelength control model, and perform wavelength tuning based on the grating area current control for the wavelength that does not meet the monitoring threshold, and the specific content is as follows: Step S1: Calculate the change in effective refractive index caused by the injected current. The calculation formula is: ,in represents the change in effective refractive index caused by the injected current, represents a constant, is the wavelength of the incident light, is the speed of light in vacuum, is the effective refractive index, represents a constant, represents the electron density, represents the hole density, represents the effective mass of the electron, represents the effective mass of the hole; Step S2: The change in the effective refractive index in step S1 generates additional optical loss. The calculation formula of the absorption coefficient of the optical loss is: ,in The absorption coefficient representing the optical loss, is the mobility of electrons, is the mobility of holes, represents a constant, is the wavelength of the incident light, is the speed of light in vacuum, is the effective refractive index, represents a constant, represents the electron density, represents the hole density, represents the effective mass of the electron, represents the effective mass of the hole; Step S3: When the change in the effective refractive index caused by the injected current meets the preset threshold range of the effective refractive index change, and the additional optical loss generated by the change in the effective refractive index meets the preset threshold range of the optical loss change, stop injecting current to complete the grating area current control.
[0023] In this embodiment, it should be specifically explained that in step S06, when the wavelength information of the active area current control in step S04 and the wavelength information of the grating area current control in step S05 are output to the monitoring background, the wavelength information is combined and processed by using a digital filter; According to the needs of wavelength information processing, different types of digital filters can be selected, including low-pass filters, high-pass filters, band-pass filters or band-stop filters. The digital filter processes the signal through an internal mathematical algorithm to eliminate or weaken unnecessary wavelength components while retaining or enhancing the required wavelength components. Signals of different wavelengths are weighted and added together. The choice of weight depends on the importance of each wavelength signal and the required merging effect. If signals of different wavelengths have a specific frequency relationship, the signals are merged into a new signal through frequency synthesis technology.
[0024] In this embodiment, it should be specifically explained that in step S07, the wavelength information after regional control output in step S06 is received, and the wavelength information is compared with the monitoring threshold in step S01. If the wavelength information after regional control output meets the monitoring threshold in step S01, the wavelength tuning of the semiconductor high-speed laser is completed. If the wavelength information after regional control output does not meet the monitoring threshold in step S01, the process returns to step S03 to perform regional control on the wavelength again.
[0025] The difference between the present embodiment and the prior art lies in that the present embodiment is provided with step S01: determining the target wavelength range, step S02: wavelength monitoring of the semiconductor high-speed laser, step S03: laser wavelength tuning area division, step S04: active area current control of the wavelength, step S05: grating area current control of the wavelength, step S06: outputting the wavelength information after regional control, step S07: receiving the wavelength information after regional control, determining the target wavelength range according to different types of semiconductor high-speed lasers, and performing wavelength monitoring on the laser signal emitted by the semiconductor high-speed laser, performing regional control on the wavelength, establishing an active area wavelength control model and a grating area wavelength control model, performing wavelength tuning based on the active area current control on the wavelength that does not meet the monitoring threshold, completing the wavelength tuning of the semiconductor high-speed laser, achieving a wide wavelength coverage range, and achieving continuous wavelength adjustability within a certain range, thereby meeting the needs of different applications. Since the semiconductor high-speed laser has high sensitivity and high accuracy, it can achieve more sophisticated experiments and detection.
[0026] Finally: The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.
[0027] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.
Claims
1. A method for tuning the wavelength of a semiconductor high-speed laser, characterized in that: The following steps are involved: Step S01: determining a target wavelength range: determining a target wavelength range according to different types of semiconductor high-speed lasers, and setting the target wavelength range as a monitoring threshold for wavelength monitoring; Step S02: wavelength monitoring of the semiconductor high-speed laser: the laser detector receives the laser signal emitted by the semiconductor high-speed laser, monitors the wavelength of the laser signal, and determines whether the wavelength meets the monitoring threshold; Step S03: Laser wavelength tuning region division: the laser wavelength tuning region is divided into an active region and a grating region, and the wavelength is controlled in different regions according to the monitoring result of the wavelength monitoring of the laser signal emitted by the semiconductor high-speed laser; Step S04: Active area current control of the wavelength: an active area wavelength control model is established according to the regional control result in step S03, and wavelength tuning is performed based on active area current control for wavelengths that do not meet the monitoring threshold; Step S05: performing grating area current control on the wavelength: establishing a grating area wavelength control model according to the regional control result in step S03, and performing wavelength tuning based on the grating area current control on the wavelength that does not meet the monitoring threshold; Step S06: Outputting wavelength information after regional control: outputting the wavelength information of active area current control in step S04 and the wavelength information of grating area current control in step S05 to the monitoring background; Step S07: receiving the wavelength information after the regional control: receiving the wavelength information after the regional control output in step S06, comparing the wavelength information with the monitoring threshold in step S01, and completing the wavelength tuning of the semiconductor high-speed laser.
2. The method for wavelength tuning of a semiconductor high-speed laser according to claim 1, characterized in that: In the step S01, the maximum value of the target wavelength range corresponds to the maximum value of the monitoring threshold, and the minimum value of the target wavelength range corresponds to the minimum value of the monitoring threshold.
3. The method for wavelength tuning of a semiconductor high-speed laser according to claim 1, characterized in that: In step S02, the laser detector receives the laser signal emitted by the semiconductor high-speed laser, and compares the wavelength value of the laser signal with the monitoring threshold of the wavelength monitoring set in step S01. If the wavelength value of the laser signal is within the monitoring threshold range, it is judged that the wavelength value of the laser signal meets the monitoring threshold. If the wavelength value of the laser signal is not within the monitoring threshold range, it is judged that the wavelength value of the laser signal does not meet the monitoring threshold, and the laser is wavelength tuned according to the wavelength value of the laser signal.
4. The method for tuning the wavelength of a semiconductor high-speed laser according to claim 1, characterized in that: In the step S03, the laser wavelength tuning area is divided into an active area and a grating area. If the wavelength value of the laser signal is less than the minimum value of the monitoring threshold, the wavelength value of the laser signal is controlled by the active area current. If the wavelength value of the laser signal is greater than the maximum value of the monitoring threshold, the wavelength value of the laser signal is controlled by the grating area current.
5. The method for tuning the wavelength of a semiconductor high-speed laser according to claim 4, characterized in that: If the wavelength value of the laser signal is less than the minimum value of the monitoring threshold, the content of the active area current control of the wavelength value of the laser signal is: establishing an active area wavelength control model, and performing wavelength tuning based on the active area current control for the wavelength that does not meet the monitoring threshold. The specific content is as follows: Step S1: Calculate the optical field gain for the wavelength that does not meet the monitoring threshold. The calculation formula is: ,in represents the light field gain value, represents the gain factor, represents the carrier density, represents the transparent carrier concentration, represents the gain compression constant, represents the photon number density; Step S2: Calculate the detuning coefficient for the wavelength that does not meet the monitoring threshold. The calculation formula is: ,in represents the detuning coefficient, represents the light field limitation factor, represents the line width enhancement factor, represents the differential gain; Step S3: Establish an active region wavelength control model to calculate the carrier wavelength tuning rate, and the calculation formula is: ,in represents the carrier wavelength tuning rate, represents the current injection efficiency, Indicates the injected current value, represents the width of the waveguide, represents the thickness of the waveguide, s represents the carrier lifetime, represents the group velocity of the light field wave packet; Step S4: When the carrier wavelength tuning rate meets the preset rate threshold range, the injection of current is stopped to complete the active region current control.
6. The method for tuning the wavelength of a semiconductor high-speed laser according to claim 4, characterized in that: If the wavelength value of the laser signal is greater than the maximum value of the monitoring threshold, the content of the grating area current control of the wavelength value of the laser signal is: establish a grating area wavelength control model, and perform wavelength tuning based on the grating area current control for the wavelength that does not meet the monitoring threshold. The specific content is as follows: Step S1: Calculate the change in effective refractive index caused by the injected current. The calculation formula is: ,in represents the change in effective refractive index caused by the injected current, represents a constant, is the wavelength of the incident light, is the speed of light in vacuum, is the effective refractive index, represents a constant, represents the electron density, represents the hole density, represents the effective mass of the electron, represents the effective mass of the hole; Step S2: The change in the effective refractive index in step S1 generates additional optical loss. The calculation formula of the absorption coefficient of the optical loss is: ,in The absorption coefficient representing the optical loss, is the mobility of electrons, represents the mobility of holes; Step S3: When the change in the effective refractive index caused by the injected current meets the preset threshold range of the effective refractive index change, and the additional optical loss generated by the change in the effective refractive index meets the preset threshold range of the optical loss change, stop injecting current to complete the grating area current control.
7. The method for tuning the wavelength of a semiconductor high-speed laser according to claim 1, characterized in that: In step S06, when the wavelength information of the active area current control in step S04 and the wavelength information of the grating area current control in step S05 are output to the monitoring background, the wavelength information is combined and processed by using a digital filter.
8. The method for wavelength tuning of a semiconductor high-speed laser according to claim 1, characterized in that: In the step S07, the wavelength information after the regional control output in step S06 is received, and the wavelength information is compared with the monitoring threshold in step S01. If the wavelength information after the regional control output meets the monitoring threshold in step S01, the wavelength tuning of the semiconductor high-speed laser is completed. If the wavelength information after the regional control output does not meet the monitoring threshold in step S01, the process returns to step S03 to perform regional control on the wavelength again.