JP2016111214A - Wavelength variable light source, control method for wavelength variable light source, and manufacturing method of wavelength variable light source - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wavelength variable light source which suppresses wavelength drift by keeping a temperature at a temperature observation point constant before and after wavelength switching by an injection current amount operation onto a semiconductor laser and suppressing slow thermal fluctuation caused by a slow response of a temperature control element (Peltier element).SOLUTION: In the wavelength variable light source, on a laser sub-mount that is disposed on the temperature control element, a semiconductor laser, a temperature observation element, and a thermal compensation region are disposed in this order via a semiconductor substrate and a temperature observed by the temperature observation element is controlled to be constant by the temperature control element. A control part previously calculates and stores power to be inputted to the semiconductor laser before and after the wavelength switching and power to be inputted to the thermal compensation region before and after the wavelength switching for cancelling a heat generation amount change caused by the power inputted to the semiconductor laser. During the operation, the power that is stored before and after the wavelength switching is inputted to the semiconductor laser and the thermal compensation region.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a wavelength tunable light source using a semiconductor laser, a control method thereof, and a manufacturing method thereof.

  In recent years, Internet traffic continues to explode due to the increase in large-capacity content such as video distribution and the spread of mobile terminals such as smartphones and tablets, and there is a strong demand for an increase in transmission capacity of optical communication systems.

  One of the core technologies is Wavelength Division Multiplexing (WDM). As a light source, instead of preparing a plurality of light sources that output only the corresponding frequency, from the viewpoint of maintenance and operation, it is optional. A variable wavelength light source capable of outputting a frequency is desired.

  In a network system, high-speed wavelength switching operation is required for a wavelength-tunable light source due to the speed of wavelength restoration for switching to a new path at the time of failure recovery and the requirement of an optical switch that is not affected by the electrical bandwidth or delay. . A promising method for realizing this is the operation of injection current of the semiconductor laser. However, the wavelength fluctuates (wavelength drift) due to a secondary thermal drift caused by a change in the amount of current.

  In order to prevent this, wavelength drift is suppressed by a control method in which a thermal compensation region is added on the semiconductor laser chip and the total power input to the semiconductor laser is not changed before and after wavelength switching (for example, Patent Document 1). reference).

JP 2008-218947 A

In the wavelength tunable light source, a temperature control element (usually a Peltier element) is used to control the temperature of the semiconductor laser, so that the temperature of the semiconductor laser is kept constant based on the temperature information at the temperature observation point. Is controlling.
In the control method according to Patent Document 1 described above, the total heat generation amount by the semiconductor laser chip is kept constant before and after the wavelength switching, but the heat generation amounts of the semiconductor laser part and the heat compensation region in the semiconductor laser chip change, respectively. The heat distribution in the semiconductor laser chip and around the semiconductor laser chip changes. As a result, the temperature in the temperature observation element (thermistor) changes, and there is a problem that the wavelength drifts due to a gradual temperature fluctuation due to the operating characteristics of the Peltier element having a large time constant and a slow rise.

  The present invention has been made to solve the above-described problems. The temperature at the temperature observation point is kept constant before and after the wavelength switching by operating the amount of injection (application) current to the semiconductor laser, and the slow response of the Peltier device. An object of the present invention is to provide a wavelength tunable light source, a control method thereof, and a manufacturing method thereof that can suppress the wavelength drift by suppressing the gradual thermal fluctuation caused by the above.

  In order to achieve the above object, a wavelength tunable light source according to the present invention includes a temperature control element, a laser submount disposed on the temperature control element, and a semiconductor substrate disposed on the laser submount. A semiconductor laser capable of arbitrarily changing the wavelength of the incident light; a thermal compensation region disposed on the laser submount; and disposed between the semiconductor substrate and the thermal compensation region on the laser submount. A temperature observation element, wherein the observed temperature is controlled to be constant by the temperature control element; first and second electric powers input to the semiconductor laser before and after wavelength switching; and In order to cancel the change in the amount of heat generated by the first and second electric powers, the third and fourth electric powers input to the thermal compensation region before and after the wavelength switching are predicted. In operation, the first and third powers are applied to the semiconductor laser and the thermal compensation region before the wavelength switching, respectively, and after the wavelength switching, the second power is supplied to the semiconductor laser and the thermal compensation region, respectively. And a control unit for supplying the fourth power.

  In the present invention, a temperature control element, a laser submount disposed on the temperature control element, and a semiconductor disposed on the laser submount via a semiconductor substrate and capable of arbitrarily changing the wavelength of emitted light. A laser, a thermal compensation region disposed on the laser submount, and a temperature observation element disposed between the semiconductor substrate and the thermal compensation region on the laser submount, wherein the observed temperature is the temperature A wavelength tunable light source control method comprising a temperature observation element controlled to be constant by a temperature control element and a control unit, wherein the control unit stores each of the semiconductor lasers before and after wavelength switching stored in advance. The thermal compensation before and after the wavelength switching to cancel the change in the amount of heat generated by the first and second powers to be input and the first and second powers. In operation, the first and third powers are applied to the semiconductor laser and the heat compensation region before the wavelength switching, respectively. After the switching, a method for controlling the wavelength tunable light source for supplying the second and fourth powers is provided.

  Furthermore, in the present invention, a temperature control element, a laser submount disposed on the temperature control element, and a semiconductor that is disposed on the laser submount via a semiconductor substrate and can arbitrarily change the wavelength of emitted light. A laser, a thermal compensation region disposed on the laser submount, and a temperature observation element disposed between the semiconductor substrate and the thermal compensation region on the laser submount, wherein the observed temperature is the temperature A wavelength tunable light source manufacturing method including a temperature observation element controlled by a temperature control element and a control unit, wherein the first and second electric power supplied to the semiconductor laser before and after wavelength switching are respectively Measuring and canceling the change in the amount of heat generated by the first and second electric powers, and the third and Of the wavelength tunable light source that stores the first to fourth powers in the control unit in advance as powers to be given to the semiconductor laser and the thermal compensation region when the wavelength is switched. A manufacturing method is provided.

  According to the wavelength tunable light source of the present invention, before and after the wavelength switching, the power input to the thermal compensation region is decreased by the increase in power input to the semiconductor laser, or the power input to the semiconductor laser is decreased. The input power to the heat compensation region increases by the amount, and the temperature in the temperature observation element is kept constant.

  Further, since the temperature control element (Peltier element) performs constant temperature control based on temperature information obtained from the temperature observation element, the driving state of the Peltier element does not change before and after wavelength switching, and the Peltier element has a large time constant. Slow wavelength drift caused by the response can be suppressed.

1 is a schematic plan view showing Embodiment 1 of a variable wavelength light source according to the present invention. It is sectional drawing when cut | disconnecting by line AA in FIG. It is a plane schematic diagram showing Embodiment 2 of the wavelength variable light source according to the present invention. It is a plane schematic diagram showing Embodiment 3 of the wavelength tunable light source according to the present invention. FIG. 9 is a schematic plan view showing Embodiment 4 of a wavelength tunable light source according to the present invention. FIG. 9 is a schematic plan view showing Embodiment 5 of a wavelength tunable light source according to the present invention.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
Embodiment 1 FIG.
FIG. 1 shows a configuration diagram according to Embodiment 1 of the present invention. The control device includes, for example, a Peltier element 1 as a temperature control element, and a laser submount 2 disposed on the Peltier element 1, and further includes a semiconductor substrate 3, a resistor 4, Further, for example, a thermistor 5 as a temperature observation element, a semiconductor laser 6 formed on the semiconductor substrate 3, and an electrode pair 7 formed so as to be electrically connected to the resistor 4 at both ends of the resistor 4 are disposed. ing. A control unit 8 is connected to the electrode pair 7.

In the cross-sectional view shown in FIG. 2, the thermistor 5 has a thermal resistance θ1 between the semiconductor laser 6 and the thermistor 5 and a thermal resistance θ2 between the resistor 4 and the thermistor 5 between the resistor 4 and the semiconductor laser 6. They are arranged to be equal (θ1 = θ2).
The thermal resistance θ between the two points is expressed by the following equation.
θ = L / (λ × A) Equation (1)
Where L is the distance between two points along the path through which heat is transferred, λ is the thermal conductivity of the substance through which heat is transferred, and A is the cross-sectional area of the path through which heat is transferred.

  In the first embodiment, the resistor 4 is thermally connected to the thermistor 5 via the laser submount 2, whereas the semiconductor laser 6 is connected to the thermistor 5 via the semiconductor substrate 3 and the laser submount 2. And thermally connected. Therefore, the positional relationship between the resistor 4, the thermistor 5, and the semiconductor laser 6 needs to be determined in consideration of the size and thermal conductivity of the semiconductor substrate 3.

  For example, assuming that there is a reference arrangement of the resistor 4, the thermistor 5, and the semiconductor laser 6 in which θ 1 = θ 2 when the semiconductor substrate 3 has a certain thermal conductivity and size (cross-sectional area), the thermal conduction of the semiconductor substrate 3 is assumed. When the rate is smaller than the reference value, the resistor 4 may be moved away from the thermistor 5 or the semiconductor laser 6 may be moved closer to the thermistor 5 as compared with the reference arrangement. On the contrary, when the thermal conductivity of the semiconductor substrate 3 is larger than the reference value, the resistor 4 may be brought closer to the thermistor 5 or the semiconductor laser 6 may be moved away from the thermistor 5 as compared with the reference arrangement.

  Regarding the size, when the cross-sectional area of the heat transfer direction of the semiconductor substrate 3 is smaller than the reference value, the resistor 4 may be moved away from the thermistor 5 or the semiconductor laser 6 may be moved closer to the thermistor 5 as compared with the reference arrangement. . On the contrary, when the cross-sectional area of the semiconductor substrate 3 in the heat transfer direction is larger than the reference value, the resistor 4 may be brought closer to the thermistor 5 or the semiconductor laser 6 may be moved away from the thermistor 5 as compared with the reference arrangement.

In this way, the thermal resistances θ1 and θ2 can be adjusted to be equal. However, it is not an essential condition for the present invention that θ1 = θ2, and as will be described later, the amount of heat generated by the semiconductor laser 6 This is a more preferable condition for canceling this change by changing the amount of heat generated by the resistor 4 that is the heat compensation region, and keeping the temperature of the thermistor 5 constant even when the wavelength is switched.
The Peltier element 1 controls the temperature of the thermistor 5 on the laser submount 2 to be constant based on temperature information obtained from the thermistor 5. Since this control circuit is well known, a description thereof is omitted and illustration is omitted.

  Next, a control method at the time of wavelength switching operation will be described. In this control method, the driving conditions (injection current and voltage values) of the semiconductor laser 6 before and after wavelength switching and the values of the applied voltage and current to the resistor 4 (see Table 1 below) are obtained “by experiments beforehand”. To do.

First, in the state where no voltage / current is applied to the resistor 4, the injection current I _L1 = 0.15 A injected into the semiconductor laser 6 that generates the wavelength λ ₁ before switching, and the accompanying semiconductor laser 6. Injected current I to semiconductor laser 6 that generates input power (first power) WL1 = 0.15 W and applied wavelength λ ₂ (λ ₁ <λ ₂ ) with applied voltage V _L1 = 1V Measure the applied power (second power) WL2 = 0.3W with _L2 = 0.25A and the applied voltage V _L2 = 1.2V accompanying this using a wavelength meter, voltmeter and ammeter, respectively. At the same time, it is stored in the control unit 8 as switching data. As a result, the difference WR1-WR2 (0.3-0.15 = 0.15W) of the input power to the semiconductor laser 6 (that is, the amount of generated heat) before and after the wavelength switching λ ₁ → λ ₂ is known.

Next, the relationship between the current I _R flowing through the applied voltage V _R to the resistance 4 acquires, obtains the condition (switch data) necessary to compensate for the difference between the power supplied to the semiconductor laser 6.
This can be obtained by calculation since the resistance value of the resistor 4 is known. That is, the total sum W1 of input power before switching is equal to the total sum W2 of input power after switching, and the difference (WR1-WR2) of input power before and after wavelength switching to the resistor 4 is the difference to the semiconductor laser 6 described above. The voltage and current before and after the wavelength switching are obtained so as to have the same value as the input power difference (WL1−WL2) (0.3−0.15 = 0.15 W) and opposite polarity.

For this reason, the applied voltage V _R1 = 1V applied to the resistor 4 before switching, and the input power WR1 = 0.2 W due to the current I _R1 = 0.2 A, and the applied voltage V _R2 = 0 applied to the resistor 4 after switching. The input power WR2 = 0.05W with .5V and current I _R2 = 0.1A is obtained, and this is also stored in the control unit 8 as switching data. This data is not unambiguous and can be determined in various ways.

As a result, the sum W1 = 0.35W of input power before wavelength switching and the sum W2 = 0.35W of input power after wavelength switching are equal to each other.
In the example of Table 1, the input power to the semiconductor laser 6 increases from 0.15 W to 0.3 W before and after the wavelength switching, and the input power to the resistor 4 increases from 0.2 W to 0.05 W. Although it decreases, when the input power to the semiconductor laser 6 decreases (λ ₁ > λ ₂ ), it indicates that the input power to the resistor 4 only needs to be increased to compensate for the decrease amount. .

The resistance value of the resistor 4 is voltage / current = 5Ω. However, the resistance value is not limited to this value, and may be less than 5Ω or greater than 5Ω. Further, the combinations of V _R1 , I _R1 , V _R2 , and I _R2 are not limited to the combinations shown in Table 1 as long as the difference in input power to the semiconductor laser 6 before and after wavelength switching can be compensated.

  The input power in Table 1 indicates the amount of heat generation, and this power is the applied current value of each of the semiconductor laser 6 and the thermal compensation region 4 that gives the power before and after the wavelength switching and the voltage value associated therewith or the applied voltage. It is only necessary that the input power difference of the semiconductor laser 6 before and after wavelength switching be a reverse input power difference of the thermal compensation region 4. In other words, there are four combinations of application to the semiconductor laser 6 and application to the resistor 4 before and after wavelength switching: voltage application-voltage application, voltage application-current application, current application-voltage application, and current application-current application. There are patterns, and any of these may be used.

At the time of wavelength switching, the voltage applied to the resistor 4 is changed to V _L2 at the timing when the voltage applied to the semiconductor laser 6 is switched to V _L2 from the pre-switching state where I _L1 is applied to the semiconductor laser 6 and V _R1 is applied to the resistor 4. _Switch to _R2 . This is performed by “feed forward control”.
In this example, the wavelength switching is performed by switching the applied voltage assuming a constant voltage source. However, the wavelength switching may be performed by switching the injection current using a constant current source. That is, from a state where the semiconductor laser 6 I _L1, the resistor 4 are injected I _R1, the current flowing through the current injected into the semiconductor laser 6 to the resistor 4 at the timing of switching the I _L2 may be switched to I _R2.

Finally, the operational effects of the present embodiment will be described.
In the present embodiment, before and after the wavelength switching, the input power to the resistor 4 is decreased by the increase of the input power to the semiconductor laser 6 or the resistance is decreased by the decrease of the input power to the semiconductor laser 6. 4 and the thermal resistance θ1 between the semiconductor laser 6 and the thermistor 5 and the thermal resistance θ2 between the resistor 4 and the thermistor 5 are equal, the temperature in the thermistor 5 is kept constant. .

  Since the Peltier element 1 performs constant temperature control based on the temperature information obtained from the thermistor 5, the driving state of the Peltier element 1 does not change before and after wavelength switching. In the present embodiment, since the resistor 4 which is a heat compensation region is formed outside the semiconductor laser 6, the temperature change of the semiconductor laser 6 caused by the change of the laser injection current is not compensated for, and the thermo-optic effect. As a result, the emission wavelength drifts. However, the drift due to the thermo-optic effect converges in about several milliseconds at most. In the present embodiment, it is possible to suppress a gradual wavelength drift caused by the response of the Peltier element 1 having a large time constant that occurs thereafter.

  In the present embodiment, the thermal resistance θ1 = θ2 and the sum of the input power to the semiconductor laser 6 and the resistor 4 before and after wavelength switching is equal, but as described above, the thermistor before and after wavelength switching. If the temperature of 5 does not change, the above equality relation θ1 = θ2 may not be strictly maintained.

Further, the temperature of the thermistor 5 before and after the wavelength switching is not strictly constant, but may be changed as long as the wavelength drift due to the change of the driving state of the Peltier element 1 is sufficiently small.
Regarding the switching operation, even if the switching of the driving conditions (voltage / current) of the semiconductor laser 6 and the resistor 4 is not strictly the same, the switching timing difference detects the temperature of the thermistor 5 and the driving conditions of the Peltier element 1 It is sufficient that the response speed of the circuit that feeds back is shorter.

  Further, the thermistor 5 may be replaced with other components as long as it is a temperature observation element, and may be a thermal diode, for example. The laser submount 2 can be made of a material having excellent thermal conductivity. For example, ceramics such as aluminum nitride and alumina can be used, but are not limited to ceramics, and silicon materials, synthetic resin materials, metal materials, and the like can be used. The element for controlling the temperature is not limited to the Peltier element, and may be a heater, for example.

Embodiment 2. FIG.
FIG. 3 shows a configuration diagram according to the second embodiment of the present invention. The second embodiment is a modification of the first embodiment. The optical waveguide 10 guides the light emitted from the semiconductor laser 6 onto the semiconductor substrate 3, and the light input by the light traveling through the optical waveguide 10. An amplifying unit 11 is arranged. The arrangement of the thermistor 5 is determined in consideration of the change in the current amount of the optical amplifying unit 11 accompanying the change in the amount of current injected into the semiconductor laser 6.
That is, since the optical amplifying unit 11 generally operates at a constant voltage, the semiconductor laser 6 may be controlled by a value obtained by subtracting the current value / voltage value of the optical amplifying unit 11 from Table 1 above.

  When the amount of current injected into the semiconductor laser 6 changes, the frequency and power of light input to the optical amplifying unit 11 change. As a result, the current amount and the heat generation amount of the optical amplifying unit 11 also change. In consideration of this influence, when the current amount switching of the semiconductor laser 6, the current amount switching of the resistor 4, and the heat generation amount change of the optical amplifying unit 11 occur simultaneously, the thermistor is located on the laser submount 2 at a position where no temperature change occurs. 5 is arranged.

  As a result, even in a configuration that obtains higher output light, the thermistor temperature does not change before and after wavelength switching, so that wavelength drift can be suppressed. Note that the thermistor temperature before and after switching may not be strictly constant as long as the wavelength drift due to the change of the driving state of the Peltier element 1 is sufficiently small.

Embodiment 3 FIG.
FIG. 4 shows a configuration diagram according to the third embodiment of the present invention. The present embodiment is a modification of the first embodiment, in which a resistance submount 9 is disposed on the laser submount 2, and a resistor 4 and an electrode pair 7 are disposed on the resistance submount 9. Since the thermal resistance between the two points is expressed by the above equation (1), if the size and thermal conductivity of the semiconductor substrate 3 and the size and thermal conductivity of the resistance submount 9 are equal, the semiconductor laser 6 to the thermistor 5 When the distance and the distance from the resistor 4 to the thermistor 5 are equal, the thermal resistance θ1 between the semiconductor laser 6 and the thermistor 5 and the thermal resistance θ2 between the resistor 4 and the thermistor are equal.

  In the present embodiment, the thermal resistance between the resistor 4 and the thermistor 5 varies depending on the material and size of the resistor submount 9, so that the degree of freedom of component placement increases. For example, given the resistance conductivity of a certain resistance submount and the resistance position at that time, if a material having a thermal conductivity larger than the reference value is selected for the resistance submount 9, the resistance 4 can be moved away from the thermistor 5 from the reference position. When a substance having a thermal conductivity smaller than the reference value is selected for the resistance submount 9, the resistor 4 can be brought closer to the thermistor 5 than the reference position.

  Considering a certain reference value of the resistance submount cross-sectional area in the heat transfer direction, if the resistance submount cross-sectional area is made larger than the reference, the resistor 4 can be moved away from the thermistor 5 from the reference position, and the resistance submount cross-section is cut off from the reference. If the area is reduced, the resistor 4 can be brought closer to the thermistor 5 than the reference position.

  The resistance submount 9 can be made of a material having excellent thermal conductivity. For example, ceramics such as aluminum nitride and alumina can be used, but are not limited to ceramics, and silicon materials, synthetic resin materials, metal materials, and the like can be used.

Embodiment 4 FIG.
FIG. 5 shows a configuration diagram of the fourth embodiment. The present embodiment is a modification of the first embodiment, and semiconductor lasers 101 to 103 are formed on a semiconductor substrate 3. The semiconductor lasers 6 have different emission wavelengths, and the wavelength range that can be emitted can be expanded by properly using them. The number of semiconductor lasers 6 may be two, or three or more.

Embodiment 5 FIG.
FIG. 6 shows a configuration diagram of the fifth embodiment. The present embodiment is a modification of the fourth embodiment. Resistors 201 to 203 are arranged on the laser submount 2, and electrode pairs 301 to 303 are provided at both ends of the resistors 201 to 203, respectively. To 303 and the control unit 8 are connected. One electrode of the electrode pairs 301 to 303 is connected to the switch 12.

During operation, the absolute value | θ1-θ2 | of the difference between the thermal resistance θ1 between the semiconductor laser 6 and the thermistor 5 and the thermal resistance θ2 between the resistor 4 and the thermistor 5 is the smallest depending on the semiconductor laser 6 to be used. The resistance 4 is measured in advance and stored in the control unit 8, and the control unit 8 switches the switch 12 during wavelength switching.
Thereby, since the temperature change of the thermistor 5 before and behind wavelength switching can be suppressed, wavelength drift can be suppressed. The number of resistors 4 may be two, or three or more. Further, the number of resistors 4 may be different from the number of semiconductor lasers 6.

  DESCRIPTION OF SYMBOLS 1 Peltier device; 2 Laser submount; 3 Semiconductor substrate; 4,201-203 Resistance (thermal compensation area); 5 Thermistor; 6,101-103 Semiconductor laser; 7,301-303 Electrode pair; 8 Control part; 9 Resistance Submount; 10 Optical waveguide; 11 Optical amplifier; 12 Switch; θ1, θ2 Thermal resistance.

Claims (11)

A temperature control element;
A laser submount disposed on the temperature control element;
A semiconductor laser disposed on the laser submount via a semiconductor substrate and capable of arbitrarily changing the wavelength of the emitted light;
A thermal compensation region disposed on the laser submount;
A temperature observation element disposed between the semiconductor substrate and the thermal compensation region on the laser submount, wherein the observed temperature is controlled to be constant by the temperature control element;
The first and second powers input to the semiconductor laser before and after the wavelength switching, and the heat compensation regions before and after the wavelength switching as canceling the change in the amount of heat generated by the first and second powers. The third power and the fourth power to be input to are previously obtained and stored, and during operation, the first and third powers are switched between the semiconductor laser and the heat compensation region before the wavelength switching, respectively. A wavelength tunable light source comprising: a control unit that turns on power and turns on the second and fourth powers after the wavelength switching. The power is configured by an applied current value of each of the semiconductor laser and the thermal compensation region and a voltage value associated therewith, or a combination of an applied voltage value and a current value associated therewith, which gives the power before and after the wavelength switching. The difference between the first power and the second power is equal to the third power difference and the fourth power difference in opposite polarity, and the control unit applies the current applied or applied to the semiconductor laser as the first power and the second power. The wavelength tunable light source according to claim 1, wherein an applied voltage or current to the thermal compensation region is changed as the third and fourth electric powers at a timing of changing the voltage. The wavelength tunable light source according to claim 1, wherein a first thermal resistance between the semiconductor laser and the temperature observation element is equal to a second thermal resistance between the temperature observation element and the thermal compensation region. On the semiconductor substrate, the semiconductor laser is formed with an optical waveguide for guiding light emitted from the semiconductor laser, and an optical amplifying unit for amplifying the light traveling in the optical waveguide, The tunable light source according to claim 1, wherein the second power is a value obtained by subtracting a constant power of the optical amplification unit. A resistive submount is disposed between the laser submount and the thermal compensation region, and the material and / or size of the resistive submount is selected so that the first and second thermal resistances are equal. The wavelength tunable light source according to claim 3. The wavelength tunable light source according to claim 1, wherein two or more semiconductor lasers are formed in parallel on the semiconductor substrate. A plurality of the thermal compensation regions are disposed on the laser submount, electrode pairs are provided at both ends of each of the thermal compensation regions, and one of each of the plurality of electrode pairs is connected to an electrical switch, The other of each of the electrode pairs is connected to a power source;
The control unit controls the electrical switch so as to select a thermal compensation region in which the temperature change of the temperature observation element before and after the wavelength switching acquired in advance is minimized according to a semiconductor laser to be used among the semiconductor lasers. The wavelength tunable light source according to claim 6 to be switched. The wavelength tunable light source according to any one of claims 1 to 7, wherein the thermal compensation region is a resistor, the temperature control element is a Peltier element or a heater, and the temperature observation element is a thermistor or a thermal diode. The wavelength tunable light source according to claim 1, wherein the laser submount is made of ceramic, silicon, synthetic resin, or metal. A temperature control element;
A laser submount disposed on the temperature control element;
A semiconductor laser disposed on the laser submount via a semiconductor substrate and capable of arbitrarily changing the wavelength of the emitted light;
A thermal compensation region disposed on the laser submount;
A temperature observation element disposed between the semiconductor substrate and the thermal compensation region on the laser submount, wherein the observed temperature is controlled to be constant by the temperature control element;
A control method of a wavelength tunable light source comprising a control unit,
The control unit presupposes that the first and second powers input to the semiconductor laser before and after wavelength switching and cancels changes in the amount of heat generated by the first and second powers. The third and fourth electric powers input to the thermal compensation region before and after wavelength switching, respectively, during operation, to the semiconductor laser and the thermal compensation region before the wavelength switching, respectively. A method for controlling a wavelength tunable light source, wherein the second power and the fourth power are respectively applied after the wavelength switching. A temperature control element;
A laser submount disposed on the temperature control element;
A semiconductor laser disposed on the laser submount via a semiconductor substrate and capable of arbitrarily changing the wavelength of the emitted light;
A thermal compensation region disposed on the laser submount;
A temperature observation element disposed between the semiconductor substrate and the thermal compensation region on the laser submount, wherein the observed temperature is controlled to be constant by the temperature control element;
A method of manufacturing a wavelength tunable light source including a control unit,
Measure first and second powers input to the semiconductor laser before and after wavelength switching,
Obtaining the third and fourth powers to be input to the thermal compensation region before and after the wavelength switching as canceling the change in the amount of heat generated by the first and second powers,
The method for manufacturing a wavelength tunable light source, wherein the first to fourth powers are stored in the control unit in advance as powers to be supplied to the semiconductor laser and the thermal compensation region when the wavelength is switched.

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