Wavelength variable laser device, optical transceiver, and wavelength control method

Abstract

A wavelength-tunable laser device (10) comprises: a semiconductor photomultiplier (121) that outputs light on the basis of supplied power; a heater (124) that heats on the basis of the supplied power to control the wavelength of the light output from the semiconductor photomultiplier; and a control unit (11) that controls the power supplied to the heater. On the basis of the wavelength of the light output from the wavelength-tunable laser device, the control unit determines a target value of the power supplied to the heater and a transition of the power supplied to the heater before the target value.

Description

Technical Field

[0001] The present disclosure relates to a wavelength tunable laser device, an optical transceiver, and a wavelength control method.

Background Art

[0002] As a light source for wavelength division multiplexing communication (WDM) that multiplexes optical signals of a plurality of wavelengths on a single optical fiber cable for communication, it is known to use a wavelength tunable laser device capable of outputting optical signals of a plurality of wavelengths.

[0003] In relation to this technology, Patent Document 1 discloses a wavelength tunable light source (wavelength tunable laser device) and an optical transceiver that extract light of a desired wavelength and transmit and receive information using silicon photonics, which is a technology for integrating various elements on a silicon substrate.

[0004] In Patent Document 1, the light output from the SOA (Semiconductor Optical Amplifier) 51 passes through a waveguide type wavelength filter (two ring resonators) from the Si waveguide, is phase-adjusted by a phase adjuster (heater), and is reflected by a partial reflection mirror. Then, due to multiple reflections between the high reflection film of the SOA 51 and the partial reflection mirror, and phase adjustment by the phase adjuster, light with enhanced intensity and aligned phase passes through the partial reflection mirror and is input from the Si waveguide to the SOA 52. Then, the light amplified from the SOA 52 is output. Further, in Patent Document 1, by energizing and heating the heater, the refractive index changes due to the thermo-optical effect of Si, and the resonance wavelength of the ring resonator changes. Thereby, it is disclosed that the transmission wavelength can be controlled.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, when forming a filter, a waveguide, or the like using silicon photonics as in the technology described in Patent Document 1, there may be a case where the wavelength of the light output to the outside cannot be appropriately controlled.

[0007] An object of the present disclosure is to provide a wavelength-variable laser device, an optical transceiver, and a wavelength control method capable of appropriately controlling the wavelength of light output to the outside in view of the above-described problems.

Means for Solving the Problems

[0008] In a first aspect according to the present disclosure, there is provided a wavelength-variable laser device including: a semiconductor optical amplifier that outputs light based on supplied power; a heater that controls the wavelength of the light output from the semiconductor optical amplifier by heating based on the supplied power; and a control unit that controls the power supplied to the heater, wherein the control unit determines a target value of the power supplied to the heater and a transition of the power supplied to the heater up to the target value based on the wavelength of the light output from the wavelength-variable laser device.

[0009] Further, in a second aspect according to the present disclosure, there are provided an optical reception module for receiving an optical signal, a wavelength-variable laser device, an optical cable interface for transmitting the light from the wavelength-variable laser device, an electrical interface for transmitting and receiving an electrical signal, and a transmission control unit that, when an optical signal is received by the optical reception module, converts it into an electrical signal and outputs it from the electrical interface, and when an electrical signal is received by the electrical interface, converts it into an optical signal and outputs it from the optical cable interface. The wavelength-variable laser device includes a semiconductor optical amplifier that outputs light based on the supplied power, a heater that controls the wavelength of the light output from the semiconductor optical amplifier by heating based on the supplied power, and a control unit that controls the power supplied to the heater. The control unit determines a target value of the power supplied to the heater and a transition of the power supplied to the heater up to the target value based on the wavelength of the light output from the wavelength-variable laser device. An optical transceiver is provided.

[0010] Further, in a third aspect according to the present disclosure, there is provided a wavelength-variable laser device including a semiconductor optical amplifier that outputs light based on the supplied power and a heater that controls the wavelength of the light output from the semiconductor optical amplifier by heating based on the supplied power. Based on the wavelength of the light output from the wavelength-variable laser device, the wavelength-variable laser device determines a target value of the power supplied to the heater and a transition of the power supplied to the heater up to the target value, and supplies power to the heater according to the determined transition. A wavelength control method is provided.

Advantages of the Invention

[0011] According to one aspect, the wavelength of the light output to the outside can be appropriately controlled.

Brief Description of the Drawings

[0012]

Figure 1A

Figure 1B

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Embodiments for Carrying Out the Invention

[0013] The principles of the present disclosure are described with reference to several exemplary embodiments. These embodiments are described for illustrative purposes only and are intended to assist those skilled in the art in understanding and implementing the present disclosure without suggesting any limitation on the scope of the present disclosure. The disclosure described herein may be implemented in various ways other than those described below. In the following description and claims, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0014] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. (Embodiment 1) <Configuration>

[0015] Referring to FIG. 1A, the configuration of the wavelength-variable laser device 10 according to the embodiment will be described. FIG. 1A is a diagram showing an example of the configuration of the wavelength-variable laser device 10 according to the embodiment. The wavelength-variable laser device 10 includes a control unit 11 and a wavelength-variable light source unit 12. The control unit 11 and the wavelength-variable light source unit 12 may be housed in the same housing. Further, the control unit 11 and the wavelength-variable light source unit 12 may be connected so as to be able to communicate with each other by a cable or the like.

[0016] The wavelength-variable light source unit 12 may be used as a light source such as wavelength division multiplexing (WDM) communication that multiplexes optical signals of a plurality of wavelengths on a single optical fiber cable for communication.

[0017] In the example of FIG. 1A, the wavelength-variable light source unit 12 includes a semiconductor optical amplifier 121, a resonator 122, a mirror 123A, a mirror 123B, a heater 124A, a heater 124B, a semiconductor optical amplifier 125, and a waveguide 126. Hereinafter, when it is not necessary to distinguish between the heater 124A and the heater 124B, at least one of the heater 124A and the heater 124B may be appropriately simply referred to as "heater 124".

[0018] The wavelength-variable light source unit 12 may be implemented, for example, by silicon photonics, which is a technology for integrating various elements on a silicon substrate (an optical circuit using a silicon semiconductor). Thereby, miniaturization of the wavelength-variable light source unit 12 can be realized. Further, since the silicon material can obtain a large refractive index change even with a small temperature change compared to the quartz material, the heating power of the heater 124 can be reduced. Therefore, power saving can be realized. In this case, for example, the semiconductor optical amplifier 121, the resonator 122, the semiconductor optical amplifier 125, and the waveguide 126 may be formed of silicon on the silicon substrate by etching or the like. The waveguide 126 formed of silicon can be referred to as a "silicon optical waveguide". Further, the heater 124, the mirror 123A, and the mirror 123B may be formed of a material other than silicon by, for example, extrapolation or baking.

[0019] The semiconductor optical amplifier 121 is a semiconductor optical amplifier (SOA) that outputs light based on the supplied power. The semiconductor optical amplifier 121 outputs light for a light source. The mirror 123A is provided on one end face side of the semiconductor optical amplifier 121 and reflects light to the other end side of the semiconductor optical amplifier 121.

[0020] The resonator 122 is a filter that extracts light of a specific wavelength. The resonator 122 may be, for example, a Vernier type variable wavelength filter using two ring resonators. Note that the ring resonator is, for example, an optical circuit formed in a ring shape, and among the light input from one straight waveguide, only the light having a specific wavelength is output from the other waveguide. Note that the resonator 122 only needs to be a filter that extracts light of a specific wavelength, and is not limited to the example using two ring resonators.

[0021] The mirror 123B may be, for example, a partial reflection mirror or the like. The heater 124A heats the resonator 122 based on the supplied power. The heater 124B heats at least a part of the waveguide 126 between the semiconductor optical amplifier 121 and the semiconductor optical amplifier 125 based on the supplied power. The heater 124 controls the wavelength of the light output from the semiconductor optical amplifier 121 by changing the refractive index of the heated part. Note that the number of heaters 124 is not limited to the example in FIG. 1A. The semiconductor optical amplifier 125 amplifies the input light and outputs the light 125A from the wavelength variable light source unit 12.

[0022] The control unit 11 controls the power supplied from a power source (not shown) to each part of the wavelength variable light source unit 12. The control unit 11 may supply, for example, the semiconductor optical amplifier 121, the heater 124, and the semiconductor optical amplifier 125 with power corresponding to the intensity and wavelength of the light to be output from the wavelength variable light source unit 12.

[0023] The control unit 11 transmits light of a specific wavelength through the resonator 122 by heating the resonator 122 with the heater 124B. Then, the control unit 11 outputs light from the semiconductor optical amplifier 121. The output light passes through the resonator 122, is phase - adjusted by the heater 124B acting as a phase modulator, and is reflected by the mirror 123B. Due to the multiple reflections between the mirror 123A and the mirror 123B and the phase adjustment by the heater 124B, light with enhanced intensity and consistent phase passes through the mirror 123B and is output from the semiconductor optical amplifier 125.

[0024] Based on the wavelength of the light output from the wavelength - variable light source unit 12 (semiconductor optical amplifier 125), the control unit 11 determines the target value of the power supplied to the heater 124 and the transition of the power supplied to the heater 124 up to the target value. Then, the control unit 11 supplies the determined power transition to the heater from the power source.

[0025] <Modification Example> FIG. 1B is a diagram showing an example of the configuration of the wavelength - variable laser device 10 according to the embodiment. In the example of FIG. 1B, compared with the example of FIG. 1A, the wavelength - variable light source unit 12 is different in that it has a wavelength locker 127 and a modulator 128. Similar to the example of FIG. 1A, the wavelength - variable light source unit 12 in FIG. 1B may also be implemented, for example, by silicon photonics (an optical circuit using a silicon semiconductor), a technology for integrating various elements on a silicon substrate.

[0026] The wavelength locker 127 fixes the frequency (oscillation frequency) of the light output from the wavelength - variable light source unit 12 to the frequency specified by the control unit 11. The wavelength locker 127 may have, for example, a mechanism for detecting the transmittance of light passing through a wavelength filter having a periodic transmittance with respect to the frequency. The control unit 11 may determine whether the oscillation frequency is different from the specified frequency based on the transmittance detected by the wavelength locker 127. And when the oscillation frequency is different from the specified frequency, the control unit 11 may control the heater 124 so that the difference between the oscillation frequency and the specified frequency is reduced.

[0027] Based on the instruction from the control unit 11, the modulator 128 continuously changes the amplitude, phase, etc. of the optical signal. The modulator 128 may be, for example, an MZ (Mach-Zender) modulator having an element (Mach-Zehnder interferometer) that splits (demultiplexes) an optical beam with the same wavelength and phase into two pairs of beams, gives different phases to each, and then combines (multiplexes) them. In this case, the control unit 11 may generate a phase difference between the two optical beams, for example, by passing an electric current through the waveguide 126 to change the refractive index. Note that the intensity of the combined optical beam changes due to the difference in the phase difference. The intensity is maximum when the phase difference is zero or 2π (360 degrees). The intensity is minimum when the phase difference is π (180 degrees).

[0028] (Embodiment 2) Next, with reference to FIG. 2, the configuration of the communication system 1 according to the embodiment will be described. <System Configuration> FIG. 2 is a diagram showing a configuration example of the communication system 1 according to the embodiment. In FIG. 2, the communication system 1 includes a communication device 2A and a communication device 2B (hereinafter, simply referred to as "communication device 2" when there is no need to distinguish). Note that the number of communication devices 2 is not limited to the example in FIG. 2. The communication device 2 has an optical transceiver 3 that mutually converts an optical signal and an electrical signal. The communication device 2A and the communication device 2B are connected by an optical communication path 201 such as an optical fiber cable so that optical communication is possible.

[0029] The communication device 2A and the communication device 2B may be, for example, a base station and an exchange station of a wireless communication system, respectively. In this case, the RAT (Radio Access Technology) of the wireless communication system may include, for example, the 6th generation mobile communication system (6G, Beyond 5G), 5G, 4G, LTE (Long Term Evolution), wireless LAN, etc.

[0030] Further, the communication device 2A and the communication device 2B may each be, for example, an optical line termination device (ONU, Optical Network Unit) that mutually converts an optical signal and an electrical signal. Note that the communication device 2A and the communication device 2B may be, for example, an optical switch that switches an optical signal communication path.

[0031] <Configuration of Optical Transceiver 3> FIG. 3 is a diagram showing a configuration example of the optical transceiver 3 according to the embodiment. In the example of FIG. 3, the optical transceiver 3 may be, for example, an SFP transceiver (small form-factor pluggable transceiver) compliant with a predetermined standard.

[0032] In the example of FIG. 3, the optical transceiver 3 includes an optical cable interface 31A, an optical cable interface 31B, an optical reception module 32, a wavelength variable light source unit 12, a transmission control unit 34, a control unit 11, and an electrical interface 35.

[0033] The optical cable interface 31A outputs the light received from an external device via an optical cable to the optical reception module 32. The optical reception module 32 converts the received optical signal into an electrical signal and outputs it to the transmission control unit 34. The transmission control unit 34 outputs an electrical signal based on the electrical signal input from the optical reception module 32 via the electrical interface 35.

[0034] Further, the transmission control unit 34 outputs an electrical signal based on the electrical signal received via the electrical interface 35 to the control unit 11. The control unit 11 controls the wavelength variable light source unit 12 based on the electrical signal from the transmission control unit 34 and causes an optical signal corresponding to the electrical signal to be output from the optical cable interface 31B.

[0035] <Hardware Configuration> FIG. 4 is a diagram showing a hardware configuration example of the control unit 11 according to the embodiment. Note that the hardware configuration of the transmission control unit 34 may be the same as that of the control unit 11. In the example of FIG. 4, the control unit 11 (computer 100) includes a processor 101, a memory 102, and a communication interface 103. These components may be connected by a bus or the like. The memory 102 stores at least a part of the program 104. The communication interface 103 includes an interface necessary for communication with other network elements.

[0036] When the program 104 is executed by the cooperation of the processor 101, the memory 102, etc., at least part of the processing of the embodiment of the present disclosure is performed by the computer 100. The memory 102 may be of any type suitable for a local technology network. The memory 102 may be, as a non-limiting example, a non-transitory computer-readable storage medium. Also, the memory 102 may be implemented using any suitable data storage technology such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory, and removable memory. Although only one memory 102 is shown for the computer 100, there may be several physically different memory modules in the computer 100. The processor 101 may be of any type. The processor 101 may include a general-purpose computer, a dedicated computer, a microprocessor, a digital signal processor (DSP), and one or more processors based on a multi-core processor architecture as a non-limiting example. The computer 100 may have a plurality of processors such as an application-specific integrated circuit chip that is temporally dependent on a clock that synchronizes the main processor.

[0037] Embodiments of the present disclosure may be implemented in hardware or dedicated circuitry, software, logic or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software that may be executed by a controller, microprocessor or other computing device.

[0038] The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer-readable storage medium. The computer program product includes computer-executable instructions, such as instructions included in program modules, which are executed on a device on a target actual processor or virtual processor to execute the processes or methods of the present disclosure. Program modules include routines, programs, libraries, objects, classes, components, data structures, etc. that perform specific tasks or implement specific abstract data types. The functions of program modules may be combined or divided among program modules as desired in various embodiments. The machine-executable instructions of program modules can be executed within a local or distributed device. In a distributed device, program modules can be arranged on both local and remote storage media.

[0039] The program code for executing the method of the present disclosure may be written in any combination of one or more programming languages. This program code is provided to a processor or controller of a general-purpose computer, a dedicated computer, or other programmable data processing device. When the program code is executed by the processor or controller, the functions / operations in the flowchart and / or the implementation block diagram are executed. The program code is executed entirely on the machine, partly on the machine, as a stand-alone software package, partly on the machine, partly on a remote machine, or entirely on a remote machine or server.

[0040] The program can be stored using various types of non - transient computer - readable media and supplied to a computer. Non - transient computer - readable media include various types of tangible recording media. Examples of non - transient computer - readable media include magnetic recording media, magneto - optical recording media, optical disk media, semiconductor memories, etc. Magnetic recording media include, for example, flexible disks, magnetic tapes, hard disk drives, etc. Magneto - optical recording media include, for example, magneto - optical disks, etc. Optical disk media include, for example, Blu - ray disks, CD (Compact Disc) - ROM (Read Only Memory), CD - R (Recordable), CD - RW (ReWritable), etc. Semiconductor memories include, for example, mask ROM, PROM (Programmable ROM), EPROM (Erasable PROM), flash ROM, RAM (random access memory), etc. Also, the program may be supplied to the computer by various types of transient computer - readable media. Examples of transient computer - readable media include electrical signals, optical signals, and electromagnetic waves. Transient computer - readable media can supply the program to the computer via wired communication channels such as electric wires and optical fibers, or wireless communication channels.

[0041] <Processing> Referring to FIGS. 5 to 9, an example of the processing of the control unit 11 according to the embodiment will be described. FIG. 5 is a sequence diagram showing an example of the processing of the control unit 11 according to the embodiment. FIG. 6 is a diagram showing an example of the data recorded in the setting table 601 according to the embodiment. FIG. 7 is a diagram showing an example of the wavelength output when power is supplied to the heater 124 in each of a plurality of transitions. FIG. 8 is a diagram showing an example of the transition when transitioning from a power value lower than the target value Wt to the target value Wt. FIG. 9 is a diagram showing an example of the transition when transitioning from a power value higher than the target value Wt to the target value Wt.

[0042] In step S101, the control unit 11 determines (identifies, decides) the wavelength (channel) of the light output from the wavelength-variable light source unit 12. Here, the control unit 11 may determine the wavelength of the light, for example, according to the electrical signal from the transmission control unit 34.

[0043] Subsequently, the control unit 11 determines, based on the wavelength of the light output from the wavelength-variable light source unit 12, the target value of the power supplied to the heater 124 and the transition of the power supplied to the heater 124 until the target value is reached (step S102). Thereby, for example, appropriate response characteristics can be obtained according to the hysteresis (history phenomenon, history effect) of the waveguide 126 such as silicon.

[0044] Here, the control unit 11 may determine the power supplied to the heater 124 with reference to the setting table 601 in FIG. 6. Note that the control unit 11 may store the setting table 601 for each heater 124. In this case, the control unit 11 may store the setting table 601A for the heater 124A and the setting table 601B for the heater 124B. Note that the information in the setting table 601 may be recorded in the control unit 11 in advance, for example.

[0045] In the example of FIG. 6, in the setting table 601, the wavelength, the target value, and the transition are recorded (set, registered) in association with the channel ID. The channel ID is, for example, identification information of the wavelength in wavelength division multiplexing communication. The wavelength is the wavelength of the light of the channel related to the channel ID. The target value is the target value (target value, set value) of the power supplied to the heater 124. The transition is information indicating the transition of the value of the power supplied to the heater 124 until the target value is reached. The information indicating the transition may include, for example, the information of the power value supplied at each time point from the time point when the power supply starts to the time point when the target value is reached. Or, the information indicating the transition may include, for example, the information indicating the pattern of the transition.

[0046] Even when supplying the same target power, due to the hysteresis of the waveguide 126 such as silicon, at least one of the intensity and wavelength of the light output according to the transition of the power supplied to the heater 124 may be different. Note that hysteresis means, for example, that the state of a certain system changes depending not only on the currently applied force but also on the forces applied in the past.

[0047] FIG. 7 shows an example of the wavelength output when power is supplied to the heater 124 in each of a plurality of transitions in order to output light of a specific wavelength (desired wavelength) from the wavelength-variable light source unit 12. The broken line 711B shows the difference between the desired wavelength and the wavelength actually output when the power supplied to the heater 124 is gradually decreased from about 0.7 mW to about 0 mW. Also, the broken line 711A shows the intensity of the light output at that time. Also, the broken line 712B shows the difference (wavelength difference) between the desired wavelength and the wavelength actually output when the power supplied to the heater 124 is gradually increased from about 1.1 mW to about 1.9 mW. Also, the broken line 712A shows the intensity of the light output at that time.

[0048] Also, the broken line 713B shows the difference between the desired wavelength and the wavelength actually output when the power supplied to the heater 124 is gradually decreased from about 4.5 mW to about 2.1 mW. Also, the broken line 713A shows the intensity of the light output at that time. Also, the broken line 714B shows the difference between the desired wavelength and the wavelength actually output when the power supplied to the heater 124 is gradually increased from about 4.9 mW to about 5.8 mW. Also, the broken line 714A shows the intensity of the light output at that time.

[0049] As shown by the broken line 713B, when the power supplied to the heater 124 is gradually decreased from about 4.5 mW to about 2.1 mW, at the power value 702 of about 3.2 mW, the difference between the desired wavelength and the actually output wavelength becomes 0.

[0050] Also, when the power supplied to the heater 124 is gradually decreased from about 4.5 mW to about 2.1 mW, as shown by the broken line 713A, the transition of the intensity of the output light has a peak shape and becomes the peak at the power value 702. Therefore, by setting the transition of the power supplied to the heater 124 to be a transition from a power value higher than the power value 702 to the power value 702, the response characteristics of the intensity of the light output from the wavelength-variable light source unit 12 can be stabilized. In FIG. 7, the broken line in the case of setting the transition from a power value lower than the power value 702 to the power value 702 is not shown because the transition of the intensity of the output light does not become a desired shape (for example, peak shape). Note that for each of a plurality of desired wavelengths, the intensity of the output light may be different for each transition of the power supplied to the heater 124.

[0051] Subsequently, the control unit 11 supplies power from the power supply to the heater 124 of the wavelength-variable light source unit 12 with the determined target value and transition (step S103). Here, when the wavelength of the light output from the wavelength-variable light source unit 12 (the light output from the wavelength-variable laser device 10) is the first wavelength, the control unit 11 may increase the power supplied to the heater 124 from a first power value lower than the first target value corresponding to the first wavelength to the first target value. Further, when the wavelength of the light output from the wavelength-variable light source unit 12 is a second wavelength different from the first wavelength, the control unit 11 may decrease the power supplied to the heater from a second power value higher than the second target value corresponding to the second wavelength to the second target value.

[0052] Further, the control unit 11 supplies power corresponding to the power (circulating power) at which the phase of the wavelength of the light output from the wavelength-variable light source unit 12 circulates (the phase shifts by 2π) to the heater 124, and then supplies power to the heater 124 according to the transition of the power corresponding to the wavelength until the target value of the power corresponding to the wavelength is reached. Thereby, for example, the hysteresis (history phenomenon, history effect) of the waveguide 126 such as silicon is reduced (reset, initialized), and the wavelength of the light output from the wavelength-variable light source unit 12 to the outside can be appropriately controlled. Note that hysteresis means, for example, that the state of a certain system changes depending not only on the currently applied force but also on the forces applied in the past. Note that the circulating power may be different for each wavelength of the light output from the wavelength-variable light source unit 12.

[0053] FIG. 8 shows an example of the transition 801 of the power value at each time point when transitioning from a power value lower than the target value Wt to the target value Wt of the power to be supplied to the heater 124 according to the desired wavelength. In the example of FIG. 8, the power supplied to the heater 124 increases from 0 mW to the circulating power Ws during the period from time point t0 to time point t1, is constant during the period from time point t1 to time point t2, and decreases from the circulating power Ws to 0 mW during the period from time point t2 to time point t3. Then, the period from time point t3 to time point t4 is constant, and during the period from time point t4 to time point t5, it increases from 0 mW, which is lower than the target value Wt, to the target value Wt and then becomes constant.

[0054] FIG. 9 shows an example of the transition 901 of the power value at each time point when transitioning from a power value higher than the target value Wt to the target value Wt of the power to be supplied to the heater 124 according to the desired wavelength. In the example of FIG. 9, similar to the example of FIG. 8, the power supplied to the heater 124 increases from 0 mW to the circulating power Ws during the period from time point t0 to time point t1, and is constant during the period from time point t1 to time point t2. Thereafter, during the period from time point t2 to time point t6, it decreases from the circulating power Ws, which is higher than the target value Wt, to the target value Wt and then becomes constant.

[0055] <Modification Example> The control unit 11 may be implemented by, for example, one or more computers. Also, each part (each unit) of the wavelength variable laser device 10 and the optical transceiver 3 may be formed as an integrated module or as separate modules. When a plurality of units are formed as an integrated module, the plurality of units may be accommodated, for example, in the same housing or mounted on the same circuit board.

[0056] Note that the present invention is not limited to the above-described embodiments, and can be appropriately modified without departing from the spirit thereof.

[0057] Some or all of the above-described embodiments may be described as follows in the appended claims, but are not limited thereto. (Appended Claim 1) A wavelength variable laser device, a semiconductor optical amplifier that outputs light based on supplied power; a heater that controls the wavelength of the light output from the semiconductor optical amplifier by heating based on supplied power; and a control unit that controls the power supplied to the heater, wherein the control unit determines a target value of the power supplied to the heater and a transition of the power supplied to the heater up to the target value based on the wavelength of the light output from the wavelength variable laser device. Wavelength variable laser device. (Appended Claim 2) The control unit, when the wavelength of the light output from the wavelength variable laser device is a first wavelength, increases the power supplied to the heater from a first power value lower than a first target value corresponding to the first wavelength to the first target value, and when the wavelength of the light output from the wavelength variable laser device is a second wavelength different from the first wavelength, decreases the power supplied to the heater from a second power value higher than a second target value corresponding to the second wavelength to the second target value. The wavelength variable laser device according to Appended Claim 1. (Appended Claim 3) The control unit, Associating with each of a plurality of wavelengths of light output from the wavelength-variable laser device, storing a target value of the power supplied to the heater and a transition of the power supplied to the heater up to the target value. The wavelength-variable laser device according to Appendix 1 or 2. (Appendix 4) After supplying power corresponding to the power at which the phase of the wavelength of the light output from the wavelength-variable laser device circulates to the heater, the control unit causes the heater to be supplied with power in accordance with the transition of the power corresponding to the wavelength up to the target value of the power corresponding to the wavelength. The wavelength-variable laser device according to any one of Appendices 1 to 3. (Appendix 5) The heater changes the refractive index of the light output from the semiconductor optical amplifier by heating the silicon optical waveguide. The wavelength-variable laser device according to any one of Appendices 1 to 4. (Appendix 6) An optical reception module that receives an optical signal; A wavelength-variable laser device; An optical cable interface that transmits the light from the wavelength-variable laser device; An electrical interface that transmits and receives electrical signals; A transmission control unit that, when an optical signal is received by the optical reception module, converts it into an electrical signal and outputs it from the electrical interface, and when an electrical signal is received by the electrical interface, converts it into an optical signal and outputs it from the optical cable interface. The wavelength-variable laser device includes: A semiconductor optical amplifier that outputs light based on the supplied power; A heater that controls the wavelength of the light output from the semiconductor optical amplifier by heating based on the supplied power; A control unit that controls the power supplied to the heater. The control unit determines a target value of the power supplied to the heater and a transition of the power supplied to the heater up to the target value based on the wavelength of the light output from the wavelength-variable laser device. Optical transceiver. (Appendix 7) When the wavelength of the light output from the wavelength-variable laser device is the first wavelength, the power supplied to the heater is increased from a first power value lower than the first target value corresponding to the first wavelength to the first target value. When the wavelength of the light output from the wavelength-variable laser device is a second wavelength different from the first wavelength, the power supplied to the heater is decreased from a second power value higher than the second target value corresponding to the second wavelength to the second target value. The optical transceiver according to Appendix 6. (Appendix 8) A semiconductor optical amplifier that outputs light based on the supplied power, A wavelength-variable laser device having a heater that controls the wavelength of the light output from the semiconductor optical amplifier by heating based on the supplied power. Based on the wavelength of the light output from the wavelength-variable laser device, determine the target value of the power supplied to the heater and the transition of the power supplied to the heater up to the target value. Supply power to the heater according to the determined transition. Wavelength control method.

Explanation of reference numerals

[0058] 1 Communication system 2 Communication device 3 Optical transceiver 10 Wavelength-variable laser device 11 Control unit 12 Wavelength-variable light source unit 31A Optical cable interface 31B Optical cable interface 32 Optical reception module 34 Transmission control unit 35 Electrical interface 121 Semiconductor optical amplifier 122 Resonator 123A Mirror 123B Mirror​ 124 Heater 125 Semiconductor optical amplifier 126 Waveguide 127 Wavelength locker 128 Modulator 601 Setting table

Claims

1. A wavelength-variable laser device, comprising: a semiconductor optical amplifier that outputs light based on supplied power; a heater that controls the wavelength of the light output from the semiconductor optical amplifier by heating based on supplied power; a control unit that controls the power supplied to the heater, wherein the control unit determines a target value of the power supplied to the heater and a transition of the power supplied to the heater up to the target value based on the wavelength of the light output from the wavelength-variable laser device; the control unit supplies power to the heater according to the power corresponding to the phase of the wavelength of the light output from the wavelength-variable laser device, and then supplies power to the heater according to the transition of the power corresponding to the wavelength up to the target value of the power corresponding to the wavelength; A wavelength-variable laser device.

2. The control unit: when the wavelength of the light output from the wavelength-variable laser device is a first wavelength, increases the power supplied to the heater from a first power value lower than a first target value corresponding to the first wavelength to the first target value; when the wavelength of the light output from the wavelength-variable laser device is a second wavelength different from the first wavelength, decreases the power supplied to the heater from a second power value higher than a second target value corresponding to the second wavelength to the second target value. The wavelength-variable laser device according to Claim 1.

3. The control unit: stores, in association with each of a plurality of wavelengths of the light output from the wavelength-variable laser device, a target value of the power supplied to the heater and a transition of the power supplied to the heater up to the target value. The wavelength-variable laser device according to Claim 1 or 2.

4. The heater changes the refractive index of the light output from the semiconductor optical amplifier by heating a silicon optical waveguide. The wavelength-variable laser device according to any one of Claims 1 to 3.

5. an optical reception module that receives an optical signal; a wavelength-variable laser device; an optical cable interface that transmits the light from the wavelength-variable laser device; an electrical interface that transmits and receives electrical signals; a transmission control unit that, when an optical signal is received by the optical reception module, converts it into an electrical signal and outputs it from the electrical interface, and when an electrical signal is received by the electrical interface, converts it into an optical signal and outputs it from the optical cable interface; wherein the wavelength-variable laser device: A semiconductor optical amplifier that outputs light based on supplied power, a heater that controls the wavelength of the light output from the semiconductor optical amplifier by heating based on the supplied power, and a control unit that controls the power supplied to the heater, wherein the control unit determines a target value of the power supplied to the heater and a transition of the power supplied to the heater up to the target value based on the wavelength of the light output from the wavelength-variable laser device, and the control unit supplies power to the heater according to a transition of the power corresponding to the wavelength up to a target value of the power corresponding to the wavelength after supplying power corresponding to the power at which the phase of the wavelength of the light output from the wavelength-variable laser device circulates, to the heater. An optical transceiver.

6. The control unit, when the wavelength of the light output from the wavelength-variable laser device is a first wavelength, increases the power supplied to the heater from a first power value lower than a first target value corresponding to the first wavelength to the first target value, and when the wavelength of the light output from the wavelength-variable laser device is a second wavelength different from the first wavelength, decreases the power supplied to the heater from a second power value higher than a second target value corresponding to the second wavelength to the second target value. The optical transceiver according to claim 5.

7. A semiconductor optical amplifier that outputs light based on supplied power, a heater that controls the wavelength of the light output from the semiconductor optical amplifier by heating based on the supplied power, wherein a wavelength-variable laser device having the heater determines a target value of the power supplied to the heater, a transition of the power supplied to the heater up to the target value, and power corresponding to the power at which the phase of the wavelength of the light output from the wavelength-variable laser device circulates, based on the wavelength of the light output from the wavelength-variable laser device, and supplies power to the heater according to the determined transition. A wavelength control method.

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