CN118367442A - Laser system and wavelength adjusting method - Google Patents

Abstract

The embodiment of the present application provides a laser system and a wavelength adjustment method. The laser system includes a laser, a power supply, a current monitoring circuit and a processor; the current monitoring circuit is used to obtain a monitoring current, and the monitoring current is at least one of a light detection PD current or an electrical absorption modulation EA current; the processor is used to set the multiple preset tuning current values for the power supply; the multiple preset tuning current values and the multiple monitoring current values are used for fitting to obtain a corresponding relationship curve between the monitoring current and the tuning current; multiple extreme values of the monitoring current are obtained according to the corresponding relationship curve; according to the multiple extreme values, multiple tuning current values required by the power supply when the laser system is working are obtained, and the multiple tuning current values correspond to multiple wavelengths of the laser respectively. The laser system and wavelength adjustment method provided by the embodiment of the present application facilitate the device-level and module-level detection, and improve the efficiency of laser wavelength adjustment.

Description

Laser system and wavelength adjustment method

Technical Field

The present application relates to the field of laser technology, and in particular to a laser system and a wavelength adjustment method.

Background technique

Lasers are devices that can emit lasers. They are mainly used in various information scanning, optical fiber communications, laser ranging, laser radar, etc., and various applications are constantly being developed and popularized. In order to further reduce costs, distributed Bragg reflector (DBR) lasers with better wavelength yield can be used in communication systems. They are tunable lasers, and the output wavelength is usually adjusted through temperature control technology. Since the operating temperature of the laser changes with the external environment, the output wavelength will drift significantly or even jump. Therefore, how to automatically adjust the wavelength at various operating temperatures has become the key to the application. At the same time, how to achieve light wavelength locking is also a problem that needs to be solved in practical applications.

In order to detect the wavelength of the laser light, the existing technical solution monitors the peak wavelength or spectrum of the device light through a wavelength detector or an oscillation mode detector. The wavelength detector can detect a limited range of wavelengths, and may not be able to cover scenes with large wavelength intervals for multi-channel devices; at the same time, adding optical components such as detectors to the device optical path will increase the cost, device size and product reliability risks. In order to achieve wavelength adjustment and locking, the existing technical solution detects the optimal working point of each channel through a wavelength meter or a spectrum analyzer, sets wavelength selection information such as a lookup table, and obtains the relationship between the laser wavelength and the heater temperature based on the lookup table information. By looking up the table to determine the working point of each channel, it is necessary to power on the heater and chip at the device level and the module level, which has low detection efficiency, high testing cost, and is easy to introduce test system errors that affect control accuracy; at the same time, this method is based on the test state of the comparison table is completely consistent with the product life cycle environment, and considering the differences in device and module environments, chip life and reliability processes, etc., the corresponding relationship of the comparison table may change and cannot be adjusted in real time, which will cause deviation accumulation and affect system capabilities. Therefore, how to conveniently and effectively achieve the adjustment and locking of any wavelength is a problem to be solved in current research.

Summary of the invention

The embodiments of the present application provide a laser system and a wavelength adjustment method, which facilitate device-level and module-level detection and improve the efficiency of laser wavelength adjustment.

In a first aspect, an embodiment of the present application provides a laser system, including a laser, a power supply, a current monitoring circuit and a processor; the laser is used to generate laser light; the power supply is coupled to the laser and is used to output a tuning current to the laser with a plurality of preset tuning current values so as to tune the laser; the current monitoring circuit is used to obtain a monitoring current and generate a plurality of monitoring current values of the monitoring current in the tuning, wherein the monitoring current includes at least one of a photodetection PD current or an electrical absorption modulation EA current, and the plurality of monitoring current values respectively correspond to the plurality of preset tuning current values, and each preset tuning current value corresponds to a wavelength of the laser; the processor is respectively coupled to the power supply and the current monitoring circuit and is used to: set the plurality of preset tuning current values for the power supply; fit the plurality of preset tuning current values and the plurality of monitoring current values to obtain a corresponding relationship curve between the monitoring current and the tuning current; obtain a plurality of extreme values of the monitoring current according to the corresponding relationship curve; obtain a plurality of tuning current values required by the power supply when the laser system is working according to the plurality of extreme values, and the plurality of tuning current values respectively correspond to a plurality of wavelengths of the laser. In the embodiment of the present application, the monitoring current indirectly reflects the wavelength condition of the laser. The monitoring current includes at least one of the light detection PD current and the electric absorption modulation EA current, which is easy to obtain, easy to implement device and module level detection, and has higher detection efficiency. In the embodiment of the present application, the wavelength adjustment process of the laser system is divided into an adjustment process and a working process. During the adjustment process, the processor obtains a plurality of tuning current values required by the power supply when the laser system is working according to the extreme value of the monitoring current, and directly selects the tuning current value corresponding to the target wavelength as the working point during operation, thereby improving the efficiency of wavelength adjustment and locking when the laser system is working. At the same time, the monitoring current and the tuning current are non-monotonic. The processor adjusts the tuning current value of the laser to the tuning current value corresponding to the extreme value of the monitoring current through the power supply, which can ensure that the tuning current value of the laser is within the laser mode and will not jump to other modes to prevent the laser from jumping modes.

In combination with the first aspect, in one implementation of the embodiment of the present application, the laser system further includes a photodetector for detecting the laser to generate the PD current. In this implementation, the photodetector can generate a PD current as a monitoring current while monitoring the output light power of the laser. Optionally, the photodetector can be used as part of the power detection in the laser chip, and directly respond to changes in the output light of the laser chip, thereby avoiding the influence of the external environment or optical path structure on the detection accuracy.

In combination with the first aspect, in one implementation of the embodiment of the present application, the laser system further includes an electro-absorption modulator for modulating the laser to generate the EA current. In this implementation, the electro-absorption modulator can generate the EA current as a monitoring current while modulating the laser. Optionally, the electro-absorption modulator can be used as a part of the laser chip to directly respond to changes in the light emitted by the laser chip, thereby avoiding the influence of the external environment or optical path structure on the detection accuracy.

In combination with the first aspect, in an implementation manner of the embodiment of the present application, any two adjacent preset tuning current values among the multiple preset tuning current values are separated by a preset value.

In combination with the first aspect, in one implementation of the embodiment of the present application, the processor is further used to: determine the preset value according to the tuning efficiency of the laser and the current sampling resolution of the monitoring current.

In combination with the first aspect, in one implementation of the embodiment of the present application, when the laser system is working, the processor is further used to: select a target tuning current value from the multiple tuning current values according to the target wavelength of the laser; and control the power supply to output the tuning current at the target tuning current value. In this implementation, when the laser system is working, the processor avoids the tedious calculation process for the target tuning current value, and only needs to select the tuning current value corresponding to the target wavelength from the multiple tuning current values obtained by the preset process, which simplifies the calculation process, shortens the calculation time, and improves the efficiency of wavelength adjustment.

In combination with the first aspect, in one implementation of the embodiment of the present application, the tuning current is the current output by the power supply to the heater in the grating region of the laser. In this implementation, the adjustment lock is performed based on the heater current instead of temperature control by a thermoelectric cooler, thereby improving the wavelength adjustment accuracy.

In combination with the first aspect, in one implementation of the embodiment of the present application, the laser is a distributed Bragg DBR laser.

In combination with the first aspect, in one implementation of the embodiment of the present application, the laser system further includes a memory coupled to the processor, the memory stores instructions, and the processor calls and executes the instructions.

In a second aspect, an embodiment of the present application provides a method for adjusting the laser wavelength in a laser system, comprising: setting a plurality of preset tuning current values for a power supply; outputting a tuning current to a laser through the power supply at the plurality of preset tuning current values to tune the laser, wherein the laser is used to generate a laser; obtaining a monitoring current, and generating a plurality of monitoring current values of the monitoring current in the tuning, wherein the monitoring current is used to reflect the wavelength of the laser and includes at least one of a photodetection PD current and an electrical absorption EA current, wherein the plurality of monitoring current values respectively correspond to the plurality of preset tuning current values, and each preset tuning current value corresponds to a wavelength of the laser; fitting the plurality of preset tuning current values and the plurality of monitoring current values to obtain a correspondence curve between the monitoring current and the tuning current; obtaining a plurality of extreme values of the monitoring current according to the correspondence curve; obtaining a plurality of tuning current values required by the power supply when the laser system is working according to the plurality of extreme values, wherein the plurality of tuning current values respectively correspond to a plurality of wavelengths of the laser. In the embodiment of the present application, the implementation process of the laser wavelength adjustment method is divided into an adjustment process and a working process. In the adjustment process, multiple tuning current values required by the power supply when the laser system is working are obtained according to the extreme value of the monitoring current, and the tuning current value corresponding to the target wavelength is selected as the working point during operation, thereby improving the efficiency of wavelength adjustment and locking. At the same time, the monitoring current and the tuning current are in a non-monotonic relationship. Adjusting the tuning current value to the tuning current value corresponding to the extreme value of the monitoring current can ensure that the tuning current value of the laser is within the laser mode and will not jump to other modes, thereby preventing the laser from mode jumping.

In combination with the second aspect, in one implementation of the embodiment of the present application, the PD current is generated by a photodetector in the laser system; and the EA current is generated by an electro-absorption modulator in the laser system.

In combination with the second aspect, in an implementation manner of the embodiment of the present application, any two adjacent preset tuning current values among the multiple preset tuning current values are separated by a preset value.

In combination with the second aspect, in an implementation manner of the embodiment of the present application, the method further includes: determining the preset value according to the tuning efficiency of the laser and the current sampling resolution of the monitoring current.

In combination with the second aspect, in one implementation of the embodiment of the present application, when the laser system is working, the method also includes: outputting a tuning current to the laser through a power supply to make the laser emit light; selecting a target tuning current value from the multiple tuning current values according to the target wavelength of the laser; and controlling the power supply to output the tuning current at the target tuning current value.

In combination with the second aspect, in one implementation of the embodiment of the present application, the tuning current is the current output by the power supply to the heater in the grating region of the laser.

In combination with the second aspect, in one implementation of the embodiment of the present application, the laser is a distributed Bragg DBR laser.

In a third aspect, an embodiment of the present application provides a computer-readable storage medium, comprising program instructions, which, when executed on a computer, causes the computer to execute the method described in the second aspect.

In a fourth aspect, an embodiment of the present application provides a computer program product, comprising program instructions, which, when executed on a computer, enable the computer to execute the method described in the second aspect.

In a fifth aspect, an electronic device is provided, comprising: a circuit board, and a laser system as described in the first aspect and arranged on the circuit board. Optionally, the electronic device is an optical module, and the packaging form of the optical module includes but is not limited to SFP, CFP, QSFP, and QSFP-DD.

In a sixth aspect, an optical network is provided, comprising: one or more electronic devices as described in the fifth aspect connected via optical fibers. Generally, in a PON optical network, the electronic devices may be optical line terminals OLT and optical network units ONU, and the optical line terminals are connected to the multiple optical network units via an optical distribution network; wherein the optical transmitter of at least one of the optical line terminals and the optical network units comprises the laser system as described in the first aspect.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of a laser system provided in an embodiment of the present application;

FIG2a is a structural example diagram of a laser provided in an embodiment of the present application;

FIG2b is another structural example diagram of a laser provided in an embodiment of the present application;

FIG2c is another structural example diagram of a laser provided in an embodiment of the present application;

FIG3 is a schematic diagram of another laser system provided in an embodiment of the present application;

FIG4a is an example diagram of a relationship curve between a PD current and a tuning current provided in an embodiment of the present application;

FIG4b is an example diagram of a curve showing the relationship between wavelength and tuning current provided in an embodiment of the present application;

FIG5 is a schematic diagram of an adjustment process of a laser system wavelength adjustment method provided in an embodiment of the present application;

FIG6 is a schematic diagram of the working process of a laser system wavelength adjustment method provided in an embodiment of the present application.

Detailed ways

The embodiments of the present application provide a laser system and a wavelength adjustment method, which facilitate device-level and module-level detection and improve the efficiency of laser wavelength adjustment.

The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "corresponding to" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

In the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

The wavelength-adjustable laser system provided in the embodiment of the present application can be applied to the field of optical communications. For example, the laser system can be applied to an optical communication system that requires multiple wavelength lasers, for example, the laser system can be used in one or more electronic devices connected by optical fiber communication in an optical network. Specifically, the laser system can be applied to optical modules in the transmitting end of backbone networks such as multi-channel parallel transmission systems, WDM (wavelength division multiplexing, WDM) technology, dense wavelength division multiplexing systems (dense wavelength division multiplexing, DWDM), or PON (passive optical network, PON) optical networks. Optionally, the packaging form of the optical module includes but is not limited to SFP, CFP, QSFP, QSFP-DD.

The laser system provided in the embodiments of the present application can also be used in the fields of optical sensing, optical detection, laser radar, medical optical computed tomography (OCT), precision instruments, etc. For example: the laser system can be applied to electronic devices that require multiple wavelength lasers. Taking the PON optical network as an example, the electronic equipment in the PON optical network includes an optical line terminal (OLT) and multiple optical network units (ONUs), and the optical line terminal is connected to the multiple optical network units through an optical distribution network; wherein, the optical transmitter of at least one of the optical line terminal and the optical network unit includes a laser system. For another example, the laser system provided in the embodiments of the present application can also be set on the transmitting end or the circuit board of the electronic device.

Since the operating temperature of the laser changes with the external environment, the output wavelength will drift greatly or even jump. Therefore, how to automatically adjust the wavelength at various operating temperatures has become the key to laser applications. At the same time, how to achieve wavelength locking is also a problem that needs to be solved in practical applications. In order to detect the wavelength of the laser light, some solutions monitor the peak wavelength or spectrum of the light emitted by the device through a wavelength detector or an oscillation mode detector. The wavelength detector can detect a limited range of wavelengths, and may not be able to cover scenes with large wavelength intervals for multi-channel devices. At the same time, adding optical elements such as detectors to the device optical path will increase the cost, device size, and product reliability risks. In order to achieve wavelength adjustment and locking, some solutions use a wavelength meter or spectrum analyzer to detect the optimal operating point of each channel, set wavelength selection information such as a lookup table, and derive the relationship between the laser wavelength and the heater temperature based on the lookup table information. To determine the working point of each channel by looking up a table, it is necessary to power on and test the heater and chip at the device level and module level. This has low detection efficiency and high testing cost, and is prone to introducing test system errors that affect control accuracy. At the same time, temperature control through thermoelectric coolers is easily affected by the surrounding environment and has low accuracy. This method is based on the fact that the test status of the comparison table is completely consistent with the product life cycle environment. However, considering the differences in device and module environments, chip life and reliability processes, etc., the corresponding relationship in the comparison table may change and cannot be adjusted in real time, which will lead to accumulated deviations and affect system capabilities.

In summary, how to conveniently and effectively achieve the adjustment and locking of arbitrary wavelengths is a problem to be solved in current research.

The laser system and wavelength adjustment method provided in the embodiment of the present application facilitate the device-level and module-level detection, and improve the efficiency of laser wavelength adjustment. The technical solution in the embodiment of the present application will be described in detail below in conjunction with the drawings in the embodiment of the present application.

First, a laser system provided in an embodiment of the present application is described in conjunction with FIG1 , which is a schematic diagram of a laser system provided in an embodiment of the present application. The laser system includes: a laser 101 , a power supply 102 , a current monitoring circuit 103 and a processor 104 .

In an embodiment of the present application, a laser 101 is used to generate a laser, and the number of lasers 101 can be one or more. The laser 101 adopts thermal tuning, that is, the wavelength of the light is adjusted by temperature control technology. The embodiment of the present application is described in detail with the case where the laser 101 adopts thermal tuning, so the tuning current in the embodiment of the present application refers to the thermal tuning current, that is, the laser wavelength is adjusted by adjusting the current of the heater in the laser grating area, and the current is also called the heater current. In practical applications, the laser may have other tuning methods, such as electrical tuning, and its specific implementation method is similar to the embodiment of the present application. It can be implemented with reference to the embodiment of the present application, and the embodiment of the present application will not be repeated here. Optionally, the laser can be a distributed Bragg DBR laser, which has a better wavelength yield and can reduce costs when used in communication systems.

In an embodiment of the present application, the power supply 102 is coupled to the laser 101 to output a tuning current to the laser 101. Since the number of lasers 101 can be one or more, the power supply 102 can be coupled to different lasers 101 through different output ports, thereby outputting different currents to different lasers 101. The tuning current output by the power supply 102 can be precisely adjusted according to the instructions issued by the processor 104, so that the processor 104 can adjust the tuning current value of the laser through the power supply 102. Exemplarily, during the adjustment of the laser system, the power supply 102 tunes the laser 101 according to the preset tuning current value set by the processor 104; when the laser system is working, the power supply 102 tunes the laser 101 according to the target tuning current value obtained by the processor 104. Exemplarily, the power supply 102 can be a current digital to analog converter (IDAC).

In the embodiment of the present application, the current monitoring circuit 103 is used to obtain the monitoring current and generate multiple monitoring current values of the monitoring current in the tuning, wherein the monitoring current includes at least one of the photodetection PD current and the electrical absorption modulation EA current. During the laser system adjustment process, the multiple monitoring current values correspond to the multiple preset tuning current values, and each preset tuning current value corresponds to a wavelength of the laser. When the laser system is working, the current monitoring circuit 103 monitors the monitoring current in real time, compares whether the current monitoring current value is an extreme value within a certain range, and determines the wavelength locking effect of the laser 101 in the current working state, so as to make real-time adjustments.

In the embodiment of the present application, the processor 104 can be a general-purpose processor, such as but not limited to a central processing unit (CPU), or a dedicated processor, such as but not limited to a digital signal processor (DSP), an application-specific integrated circuit (ASIC) and a field programmable gate array (FPGA). In addition, the processor 104 can also be a combination of multiple processors. In particular, in the technical solution provided in the embodiment of the present application, the processor 104 can be used to execute the relevant steps of the method in the subsequent method embodiment. The processor 104 can be a processor specially designed to execute steps or operations in the subsequent method, or it can be a processor that executes steps or operations in the subsequent method by reading and executing instructions stored in a memory. The processor 104 may need to use data stored in the memory or data uploaded by the current monitoring circuit in the process of executing steps or operations in the subsequent method.

During the laser system adjustment process, the processor 104 is used to: set multiple preset tuning current values for the power supply 102; use the multiple preset tuning current values and multiple monitoring current values for fitting to obtain a corresponding relationship curve between the monitoring current and the tuning current; obtain multiple extreme values of the monitoring current according to the corresponding relationship curve; and obtain multiple tuning current values required by the power supply when the laser system is working according to the multiple extreme values, wherein the multiple tuning current values correspond to multiple wavelengths of the laser respectively. Among the multiple preset tuning current values, any two adjacent preset tuning current values are separated by a preset value, and the preset value is determined by the processor 104 according to the tuning efficiency of the laser and the current sampling resolution of the monitoring current.

When the laser system is working, the processor 104 is used to: select a target tuning current value from a plurality of tuning current values corresponding to a plurality of wavelengths generated during the adjustment process of the laser system according to the target wavelength of the laser; and control the power supply to output the tuning current at the target tuning current value. When working, the processor avoids the tedious calculation process for the target tuning current value, and only needs to select the target tuning current value corresponding to the target wavelength from the plurality of tuning current values obtained during the adjustment process, thereby simplifying the calculation process, shortening the calculation time, and improving the efficiency of laser wavelength adjustment.

In the embodiment of the present application, the monitoring current indirectly reflects the wavelength condition of the laser. The monitoring current includes at least one of the light detection PD current or the electric absorption modulation EA current, which is easy to obtain, easy to implement device and module level detection, and has higher detection efficiency. In the embodiment of the present application, the wavelength adjustment process of the laser system is divided into two parts: the adjustment process and the working process. Optionally, the adjustment process occurs before the working process. Specifically, it can be adjusted every time the laser system is started; or the processor 104 can also set a time threshold, such as adjusting once a month; or it can be adjusted in real time, that is, adjusted before each work. During the adjustment process, the processor obtains multiple tuning current values required by the power supply when the laser system is working according to the extreme value of the monitoring current, and directly selects the tuning current value corresponding to the target wavelength as the working point during work, thereby improving the efficiency of wavelength adjustment and locking when the laser system is working. At the same time, the monitoring current and the tuning current are non-monotonic. The processor adjusts the tuning current value of the laser to the tuning current value corresponding to the extreme value of the monitoring current through the power supply, which can ensure that the tuning current value of the laser is within the laser mode and will not jump to other modes to prevent the laser from jumping.

Optionally, in some embodiments, the laser system further includes a photo detector 105 (photo detector, PD), the photo detector 105 corresponds to the laser 101 one-to-one, and the photo detector is used to detect the laser generated by the laser 101 and generate a photodetection PD current. The photo detector generates a PD current as a monitoring current to reflect the wavelength of the laser while monitoring the light power of the laser 101. Optionally, the photo detector can be used as a part of the power detection of the laser chip, and has a direct response to the change of the light output of the laser chip, avoiding the influence of the external environment or the optical path structure on the detection accuracy.

Optionally, in some embodiments, the laser system further includes an electrical absorption modulator 106 (Electrical Absorption Modulator, EAM), the electrical absorption modulator 106 corresponds to the laser 101 one-to-one, and the electrical absorption modulator 106 is used to modulate the laser to generate an electrical absorption modulated EA current. The electrical absorption modulator 106 generates an EA current as a monitoring current to reflect the wavelength of the laser while modulating the laser. Optionally, the electrical absorption modulator 106 can be used as a part of the laser chip, and has a direct response to the change of the light output of the laser chip, avoiding the influence of the external environment or the optical path structure on the detection accuracy.

Exemplarily, the laser 101, the photodetector 105 and the electro-absorption modulator can be combined as shown in FIG. 2a, FIG. 2b and FIG. 2c. As shown in FIG. 2a, the laser 101 can be combined with the electro-absorption modulator 106 and the photodetector 105. The electro-absorption modulator 106 is placed in the light-emitting direction of the laser 101 to modulate the laser light generated by the laser 101 and generate the electro-absorption modulated EA current. The photodetector 105 is located in the light-emitting direction of the electro-absorption modulator 106 to monitor the light-emitting power of the modulated laser light and generate the photo-detection PD current. At this time, the monitoring current includes at least one of the PD current and the EA current. As shown in FIG. 2b, the laser 101 can be combined only with the electro-absorption modulator 106. The electro-absorption modulator 106 is placed in the light-emitting direction of the laser 101 to modulate the laser light generated by the laser 101 and generate the EA current. At this time, the monitoring current includes the EA current. As shown in FIG. 2c , the laser 101 can be combined with the photodetector 105 only. The photodetector 105 is located in the light emitting direction of the laser 101 , monitors the light emitting power of the laser 101 , and generates a PD current. In this case, the monitored current includes the PD current.

Optionally, in some embodiments, the laser system further includes a memory 107, as shown in FIG3, which is a schematic diagram of another laser system provided in an embodiment of the present application. The memory 107 is coupled to the processor 104, and the memory 107 stores instructions, and the processor 104 calls and executes the instructions. The memory 107 can be a read-only memory (ROM), or other types of static storage devices that can store static information and instructions, or a random access memory (RAM) or other types of dynamic storage devices that can store information and instructions, or an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage (including compressed optical disc, laser disc, optical disc, digital versatile disc, Blu-ray disc, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store the desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto.

The following describes the relationship between the monitoring current, tuning current, and wavelength involved in the embodiments of the present application, wherein the tuning current is a thermal tuning current, which is the current output by the power supply to the heater in the grating region of the DBR laser, and may also be referred to as a heater current. Exemplarily, taking the PD current as an example, the relationship between the PD current, tuning current, and wavelength is described in conjunction with FIG. 4a and FIG. 4b.

FIG4a is an example diagram of the relationship curve between the PD current and the tuning current provided in the embodiment of the present application. When the tuning current in the laser changes, the refractive index of the optical chip will change, and the reflection peak will change to affect the light output power. The light detector detects the light output power to obtain the PD current, so the corresponding PD current will change. During the adjustment of the laser system, the power supply 102 outputs the tuning current to the laser 101 with multiple preset tuning current values. When the tuning current of the laser 101 changes, the PD current generated by the light detector changes accordingly. The current monitoring circuit 103 obtains multiple PD current values corresponding to the multiple preset tuning current values and uploads them to the processor 104. The processor 104 fits the above multiple preset tuning current values and multiple PD current values to obtain a corresponding relationship curve such as curve 401. Curve 401 is a segmented curve, having multiple non-monotonic parabolas 4011, such as curve 401 has 6 non-monotonic parabolas 4011, each parabola 4011 has a local extreme value of the PD current, each local extreme value corresponds to a tuning current value, i.e., a heater current value, and the target tuning current value can be selected from the above tuning current values as the working point when the laser system is working. Optionally, the corresponding relationship curve 401 between the PD current and the tuning current can be adjusted each time the laser system is started; or the processor 104 can also set a time threshold, such as adjusting once a month; or it can be adjusted in real time, i.e., adjusting before each laser system works. Optionally, the corresponding relationship between the PD current and the tuning current can be in a tabular form or a formula form. In practical applications, the current relationship can also be stored in other forms, which is not limited in the embodiments of the present application.

FIG4b is an example diagram of the relationship curve between wavelength and tuning current provided in an embodiment of the present application. When the tuning current in the laser changes, the tuning situation changes, which changes the refractive index of the optical chip in the laser 101 and affects the phase, which is equivalent to adjusting the cavity length and changing the output wavelength, so that the wavelength of the output laser increases in a step-by-step manner. The numerical relationship curve corresponding to the wavelength and the tuning current is shown in FIG4b 402. Curve 402 is a segmented curve with multiple wavelength steps 4021, and each wavelength step corresponds to a laser wavelength mode. For example, when the tuning current of the laser is 0mA to about 3mA, the laser is in the first laser wavelength mode; when the tuning current of the laser is about 3mA to about 4mA, the laser is in the second laser wavelength mode, and so on. The output wavelength fluctuation range of each laser wavelength mode is small, but the corresponding tuning current range is large. For example, in curve 402 in FIG4b, when the laser outputs a wavelength of 1294.8nm to 1295nm, the tuning current range value is 2.7mA to 4.4mA. Therefore, by observing the wavelength to adjust the tuning current, the adjustment range is large, which is not conducive to wavelength locking. Optionally, the relationship between the wavelength and the tuning current is obtained through the factory settings of the laser, or obtained through current scanning, or obtained through the experience of technicians, and is not included in the steps of the laser system wavelength adjustment method in the embodiment of the present application. Optionally, the correspondence between the wavelength and the tuning current can be in the form of a table or a formula. In practical applications, the current relationship can also be stored in other forms, and the embodiment of the present application does not limit this.

According to the deduction and experimental verification of technicians, it can be concluded that each parabola 4011 in the PD and tuning current curve 401 has a one-to-one correspondence with the wavelength step 4021 in the curve 402, that is, the tuning current value range corresponding to each parabola 4011 and the corresponding wavelength step 4021 is equal, so each parabola 4011 corresponds to a wavelength mode of a laser. For example, in the curve 401 in Figure 4a, 6 parabolas correspond to 6 wavelength modes of the laser. Therefore, the relationship curve 401 between the PD current and the tuning current can be used to determine the wavelength mode, thereby locking the wavelength. Specifically, the wavelength can be determined by the local extreme value of the PD current on each parabola 4011. By adjusting the wavelength of the laser through the tuning current value corresponding to the extreme value, it can be ensured that the tuning current value of the laser is within the laser mode and will not jump to other modes, thereby preventing the laser from jumping modes. The extreme value can be a minimum value or a maximum value according to the actual situation. Therefore, when adjusting the wavelength of the laser system, multiple corresponding tuning current values can be obtained according to the extreme values of multiple PD currents during the adjustment process, and then the laser is tuned with the tuning current value corresponding to the target wavelength during operation, so that the laser output wavelength is the target wavelength. Similarly, there is a corresponding relationship between the EA current, the tuning current and the wavelength, which will not be described here.

The laser wavelength adjustment method in the laser system provided in the embodiment of the present application is divided into an adjustment process and a working process. The adjustment process of the laser wavelength adjustment method in the laser system provided in the embodiment of the present application is described below in conjunction with FIG. 5. FIG. 5 is a schematic diagram of the adjustment process of a laser system wavelength adjustment method provided in the embodiment of the present application. The wavelength adjustment method includes:

501. Setting a plurality of preset tuning current values for a power supply;

In an embodiment of the present application, the processor 104 is coupled to the power supply 102, and is used to set a plurality of preset tuning current values for the power supply within a preset tuning current interval at intervals with preset values. When the laser leaves the factory, the sum of the tuning current working intervals of the laser can be used as the preset tuning current interval. For example, the tuning current of the laser shown in FIG4a has 6 working intervals, and the preset tuning current interval is 0-8mA. The preset value can be determined according to the thermal tuning efficiency of the laser and the monitoring current sampling resolution. For example, the preset value can have a corresponding relationship with the tuning efficiency of the laser, and the specific value of the preset value can be determined according to the corresponding relationship and the tuning efficiency of the laser. The monitoring current sampling resolution is the same, and it will not be repeated here. For example, the laser corresponding to the PD and tuning current relationship curve 401 shown in FIG4a can be set to 0.1mA as the preset value, and the preset tuning current value can be evenly set in the preset tuning current interval of 0-8mA at intervals of 0.1mA.

502. Outputting a tuning current to a laser with the plurality of preset tuning current values through the power supply to tune the laser;

In an embodiment of the present application, a power supply 102 is coupled to a laser 101, and is used to output a tuning current to the laser with the plurality of preset tuning current values to tune the laser, and the laser is used to generate a laser, and the laser wavelength and the light output power of the laser change with the change of the tuning current. The tuning current is a thermal tuning current, which is the current output by the power supply to the heater in the grating region of the DBR laser, and may also be referred to as a heater current. The embodiment of the present application is described in detail using thermal tuning as an example, and other tuning methods such as electrical tuning can be implemented with reference to the embodiment of the present application, and the embodiment of the present application will not be repeated here.

503. Obtain a monitoring current, and generate a plurality of monitoring current values of the monitoring current in the tuning;

In an embodiment of the present application, the processor 104 can obtain a monitoring current value from at least one of the photodetector 105 and the electro-absorption modulator 106 according to the current monitoring circuit 103, wherein the monitoring current includes at least one of the photodetection PD current and the electro-absorption EA current, and the multiple monitoring current values correspond to the multiple preset tuning current values, respectively, and each preset tuning current value corresponds to a wavelength of the laser. If the processor 104 can directly process voltage analog signals, the current monitoring circuit 103 can be a current detection unit. If the processor 104 can process voltage digital signals, the current monitoring circuit can be a current detection unit and a voltage reporting unit. Specifically, the current detection unit is used to detect the monitoring current value and convert the monitoring current value into a voltage value. Exemplarily, the current detection unit can be a current sensor, or can be a combination of a current sensor and an operational amplifier. The voltage reporting unit is used to sample and report the voltage value from the current detection unit to the processor 104. Exemplarily, the voltage reporting unit can be a voltage digital to analog converter (VDAC). In practical applications, the current monitoring circuit may also be a circuit composed of other circuit elements, which is not limited in the embodiments of the present application.

Optionally, in some embodiments, the processor 104 may obtain the monitoring current value from at least one of the photodetector and the electro-absorption modulator only through the current detection unit. The processor 104 may integrate a voltage sampling function, that is, read the corresponding monitoring current value from the current detection unit at every preset time.

Optionally, in some embodiments, the processor 104 may directly obtain the monitoring current value from at least one of the photodetector and the electro-absorption modulator. The processor 104 may be integrated with a current sensor to identify the monitoring current value. In some cases, the processor 104 may also amplify and sample the acquired monitoring current value. In practical applications, the processor 104 may also obtain the monitoring current value in other ways, which is not limited in the embodiments of the present application.

In the embodiment of the present application, the current monitoring circuit can also be used for optical power reporting. Exemplarily, the monitoring current value has a corresponding relationship with the optical power of the DBR laser. Therefore, the monitoring current value reported by the current monitoring circuit can be converted into optical power according to the corresponding relationship to realize the reporting of optical power. The current monitoring circuit uses a photodetector or an electro-absorption modulator for real-time monitoring, and can realize the optical power reporting function. Compared with the traditional optical power reporting scheme, it saves the reporting circuit, reduces the number of device pins, optimizes the module layout, and reduces the cost.

504. Perform fitting using the multiple preset tuning current values and the multiple monitoring current values to obtain a corresponding relationship curve between the monitoring current and the tuning current;

In an embodiment of the present application, the processor 104 uses a plurality of preset tuning current values and the plurality of monitoring current values to perform mathematical fitting to obtain a corresponding relationship curve between the monitoring current and the tuning current, and stores the curve in the memory 107 for extreme value calculation. Exemplarily, the method used for curve fitting includes Lagrange interpolation, piecewise interpolation, spline fitting, and least squares method. Exemplarily, the corresponding relationship curve between the PD current and the tuning current generated by fitting is a curve 401 in FIG. 4a, which is a piecewise curve having multiple non-monotonic parabolas 4011, each of which corresponds to a wavelength mode of the laser 101 and has a local extreme point. The curve 401 has 6 parabolas 4011, and therefore corresponds to 6 wavelength modes of the laser 101. The working wavelength of the laser can be locked by finding 6 extreme points.

Optionally, the correspondence may be in a tabular form or a formula form. In practical applications, the current relationship may also be stored in other forms, which is not limited in the embodiments of the present application. The correspondence curve is obtained by fitting the multiple preset tuning current values and the multiple monitoring current values. It is understandable that each time the laser system is started, the processor 104 can measure all the preset tuning current values and the corresponding monitoring current values, thereby establishing or updating the correspondence curve. Optionally, the processor 104 may also set a time threshold, such as updating the correspondence once a month, or may update the correspondence in real time, which is not limited in the embodiments of the present application.

Optionally, the corresponding relationship may be stored in an internal memory integrated in the processor 104, or in an external memory 105 coupled to the processor 104. When the processor 104 needs the corresponding relationship, the preset corresponding relationship may be read from the internal memory or the external memory 107. The corresponding relationship is actually data stored in the memory, and may be in the form of a formula or a table, etc., which is not limited in the embodiment of the present application.

505. Obtain multiple extreme values of the monitoring current according to the corresponding relationship curve;

In an embodiment of the present application, the processor 104 obtains multiple extreme values of the monitoring current according to the corresponding relationship curve through mathematical calculation. Optionally, the mathematical calculation process of the processor 104 to determine the minimum value can directly select the highest point and the lowest point of each parabola for comparison. Optionally, the processor 104 can also find the endpoints between each parabola and the extreme points of each parabola by deriving the curve. Optionally, the processor 104 can calculate the extreme value in the process of curve fitting, and optionally, the processor 104 can also calculate the extreme value based on the fitting generated curve. Exemplarily, the relationship curve 401 between the PD current and the tuning current in Figure 4a has 6 parabolas, corresponding to the 6 wavelength modes of the laser, and 6 PD current extreme values can be obtained. Optionally, the extreme value can be a minimum value or a maximum value, which is determined according to the corresponding relationship between the monitoring current and the tuning current obtained.

506. According to the multiple extreme values, obtain multiple tuning current values required by the power supply when the laser system is working, wherein the multiple tuning current values respectively correspond to multiple wavelengths of the laser.

In the embodiment of the present application, the processor 104 obtains multiple tuning current values corresponding to the multiple extreme values according to the corresponding relationship between the monitoring current and the tuning current, and stores the multiple extreme values and the obtained multiple tuning current values in the memory 107 for use when the laser system is working. Exemplarily, the relationship curve 401 between the PD current and the tuning current in FIG4a has 6 PD current extreme values, and the corresponding 6 tuning current values can be obtained. Optionally, the multiple extreme values and the multiple tuning current values can be stored in an internal memory integrated in the processor 104, or in an external memory 107 coupled to the processor 104.

The working process of the laser system wavelength adjustment method provided in the embodiment of the present application is described below in conjunction with FIG. 6 . FIG. 6 is a schematic diagram of the working process of a laser system wavelength adjustment method provided in the embodiment of the present application. The method includes:

601. Outputting a tuning current to a laser through a power supply to make the laser emit light;

In an embodiment of the present application, a power supply 102 is coupled to a laser 101 for outputting a tuning current within a tuning current range so that the laser can emit light; when the laser leaves the factory, the tuning current working range of the laser can be used as the tuning current range, and the input current working range is similar to the working range of step 501, which will not be repeated here.

602. Select a target tuning current value from the multiple tuning current values according to a target wavelength of the laser;

In an embodiment of the present application, the processor 104 selects a corresponding target tuning current value from a plurality of stored tuning current values according to an actually required target wavelength of the laser, wherein the plurality of tuning current values are a plurality of tuning current values corresponding to a plurality of monitoring current extreme values generated during the adjustment process.

603. Control the power supply to output the tuning current at the target tuning current value.

In the embodiment of the present application, the processor 104 sends the selected target tuning current value to the power supply to control the power supply to output the tuning current at the target tuning current value, and the laser 101 generates laser light of the target wavelength in response to the target tuning current value.

In some embodiments, the laser may cause fluctuations in the laser internal chip and material due to some uncertain factors, thereby reducing the stability of the laser. Therefore, the monitoring current value can be obtained in real time through the current monitoring circuit 103, and the monitoring current value can be compared with the above-mentioned monitoring current extreme value to reflect the adjustment and locking of the wavelength. Therefore, the processor 104 can repeatedly execute step 603, dynamically update the extreme value of the monitoring current in real time, and adjust the tuning current value, so as to ensure that the laser will not jump mode and enhance the stability of the laser.

The wavelength adjustment method of the laser system in the embodiment of the present application is divided into two parts: the adjustment process and the working process. Optionally, the adjustment process occurs before the working process. Specifically, the adjustment can be performed each time the laser system is started; or the processor 104 can also set a time threshold, such as adjusting once a month; or it can be a real-time adjustment, that is, adjustment before each operation. During the adjustment process, the processor obtains multiple tuning current values required by the power supply when the laser system is working according to the extreme value of the monitoring current, and directly selects the tuning current value corresponding to the target wavelength as the working point during operation, thereby improving the efficiency of wavelength adjustment and locking when the laser system is working. At the same time, the monitoring current and the tuning current are non-monotonic. Adjusting the tuning current value to the tuning current value corresponding to the monitoring current extreme value can ensure that the tuning current value of the laser is within the laser mode and will not jump to other modes, thereby preventing the laser from jumping modes.

In the embodiment of the present application, the laser system is actually a closed-loop locking solution, and the laser 101, power supply 102, current monitoring circuit 103, and processor 104 form a closed loop. The closed-loop system can dynamically adjust the power output in real time by monitoring the corresponding relationship curve between the current and the tuning current, and change the laser phase and wavelength in real time to ensure that the laser works in the best state, which perfectly solves the problems of system aging and high precision requirements. The laser system is in the best state in real time, which reduces the system's high stability requirements and specifications for laser components, power supplies, resistors and other circuits (can be >±0.1%), and obtains reliability and supplyability that are better than the open-loop solution, reducing the system cost.

In an embodiment of the present application, a computer-readable storage medium is also provided, which is an implementation form of the memory 107 in Figure 3. A computer program is stored in the computer-readable storage medium. When at least one processor of the laser system in the embodiment of the present application executes the computer program, the device executes the laser system wavelength adjustment method described in some embodiments of Figures 5 and 6 above.

If the wavelength adjustment method of the laser system is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, read-only memory), random access memory (RAM, random access memory), disk or optical disk and other media that can store program codes.

Those of ordinary skill in the art will appreciate that the various method steps and units described in the embodiments disclosed herein can be implemented with electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the steps and components of each embodiment have been generally described in terms of function in the above description. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Those of ordinary skill in the art may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

Claims (20)

1. A laser system, comprising: Laser, used to generate laser light; a power supply, coupled to the laser, for outputting a tuning current to the laser at a plurality of preset tuning current values to tune the laser; A current monitoring circuit, used for obtaining a monitoring current and generating a plurality of monitoring current values of the monitoring current in the tuning, wherein the monitoring current includes at least one of a photodetection PD current and an electrical absorption modulation EA current, wherein the plurality of monitoring current values correspond to the plurality of preset tuning current values, respectively, and each of the preset tuning current values corresponds to a wavelength of the laser; A processor is coupled to the power supply and the current monitoring circuit, respectively, and is used to: set the multiple preset tuning current values for the power supply; use the multiple preset tuning current values and the multiple monitoring current values to perform fitting to obtain a corresponding relationship curve between the monitoring current and the tuning current; obtain multiple extreme values of the monitoring current according to the corresponding relationship curve; and obtain multiple tuning current values required by the power supply when the laser system is working according to the multiple extreme values, wherein the multiple tuning current values respectively correspond to multiple wavelengths of the laser. 2 . The system according to claim 1 , wherein the laser system further comprises: a light detector for detecting the laser to generate the PD current. 3. The system according to claim 1 or 2, characterized in that the laser system further comprises: an electro-absorption modulator for modulating the laser to generate the EA current. 4 . The system according to claim 1 , wherein any two adjacent preset tuning current values among the plurality of preset tuning current values are separated by a preset value. 5 . 5. The system according to claim 4, characterized in that The processor is further configured to determine the preset value according to the tuning efficiency of the laser and the current sampling resolution of the monitoring current. 6. The system according to any one of claims 1 to 5, characterized in that: When the laser system is working, the processor is further used to: select a target tuning current value from the multiple tuning current values according to a target wavelength of the laser; The power supply is controlled to output the tuning current at the target tuning current value. 7. The system according to any one of claims 1 to 6, characterized in that the tuning current is the current output by the power supply to the heater in the grating region of the laser. 8. The system according to any one of claims 1 to 7, characterized in that the laser is a distributed Bragg laser (DBR). 9. The laser system according to any one of claims 1 to 8, further comprising: a memory coupled to the processor, wherein the memory stores instructions, and the processor calls and executes the instructions. 10. A method for adjusting laser wavelength in a laser system, comprising: Set multiple preset tuning current values for the power supply; Outputting a tuning current to a laser with the plurality of preset tuning current values through the power supply to tune the laser, wherein the laser is used to generate laser light; Acquire a monitoring current, and generate a plurality of monitoring current values of the monitoring current in the tuning, wherein the monitoring current includes at least one of a light detection PD current and an electrical absorption EA current, wherein the plurality of monitoring current values correspond to the plurality of preset tuning current values, respectively, and each of the preset tuning current values corresponds to a wavelength of the laser; Using the plurality of preset tuning current values and the plurality of monitoring current values to perform fitting to obtain a corresponding relationship curve between the monitoring current and the tuning current; Obtaining multiple extreme values of the monitoring current according to the corresponding relationship curve; According to the multiple extreme values, multiple tuning current values required by the power supply when the laser system is working are obtained, and the multiple tuning current values correspond to multiple wavelengths of the laser respectively. 11. The method according to claim 10, characterized in that the PD current is generated by a photodetector in the laser system; and the EA current is generated by an electro-absorption modulator in the laser system. 12 . The method according to claim 10 , wherein any two adjacent preset tuning current values among the plurality of preset tuning current values are separated by a preset value. 13. The method according to claim 12, characterized in that the method further comprises: The preset value is determined according to the tuning efficiency of the laser and the current sampling resolution of the monitoring current. 14. The method according to any one of claims 10 to 13, characterized in that when the laser system is working, the method further comprises: Outputting a tuning current to the laser through a power supply so that the laser emits light; Selecting a target tuning current value from the plurality of tuning current values according to a target wavelength of the laser; The power supply is controlled to output the tuning current at the target tuning current value. 15 . The method according to claim 10 , wherein the tuning current is the current output by the power supply to the heater in the grating region of the laser. 16. The system according to any one of claims 10 to 15, characterized in that the laser is a distributed Bragg laser (DBR). 17. An electronic device comprising: a circuit board, and the laser system according to any one of claims 1 to 9 arranged on the circuit board. 18. An optical network, comprising: one or more electronic devices as claimed in claim 17 connected via optical fibers. 19. A computer-readable storage medium, characterized in that it comprises program instructions, and when the program instructions are executed on a computer, the computer is enabled to execute the method according to any one of claims 10 to 16. 20. A computer program product, characterized by comprising program instructions, which, when executed on a computer, enable the computer to execute the method according to any one of claims 10 to 16.