Unidirectional temperature control device without TEC refrigeration circuit and detector

Abstract

The utility model belongs to the technical field of semiconductor laser chips. The utility model discloses a one-way temperature control device without a TEC refrigeration circuit and a detector, and the device comprises a heat sink base which is provided with a heat insulation surface and a mounting surface which are located at two opposite ends, a laser is arranged on the mounting surface, the heat sink base comprises a heat sink base and a heat resistance gasket, and the heat resistance gasket is laid and fixed at one end of the heat sink base to form the heat insulation surface of the heat sink base; the temperature acquisition unit is arranged on the mounting surface and is close to the laser so as to acquire temperature information of the laser; and the heating unit is arranged on the mounting surface, is close to the laser and is configured to heat the laser, and the heating unit changes the input current through the received temperature information so as to change the output temperature of the heating unit. The temperature acquisition unit can be matched with the heating unit, the heating power is controlled by changing the input current of the heating unit so as to realize accurate temperature control of the laser, and compared with other temperature control technologies, the temperature control system is low in temperature control cost and high in temperature control accuracy.

Description

Technical Field

[0001] The utility model belongs to the technical field of semiconductor laser chips, and particularly relates to a unidirectional temperature control device and a detector without a TEC refrigeration circuit. Background Art

[0002] Semiconductor lasers are often applied to important fields such as laser communication, gas detection, national defense and military, and industrial testing due to their characteristics of small volume, light weight, high efficiency, low energy consumption, long service life, and direct modulation.

[0003] For example, using semiconductor lasers to detect harmful gases has very broad application prospects. According to the Beer-Lambert principle, in order to effectively detect harmful gases, the output wavelength of the semiconductor laser must be matched with the absorption peak of the gas. The output wavelength of the semiconductor laser is mainly related to the working current and the working temperature. When the current remains unchanged, the range of its output wavelength changing with temperature is 0.1nm / °C. Therefore, it is necessary to control the temperature of the semiconductor laser within an appropriate range, and the temperature fluctuation must be lower than 0.1°C, so as to ensure that the output wavelength of the laser is relatively stable. On the other hand, the increase in the working temperature of the laser will cause an increase in the threshold current and a decrease in the slope efficiency, resulting in a decrease in the output optical power as the working temperature increases.

[0004] Regarding the temperature control problem of semiconductor lasers, scholars and research institutions at home and abroad have carried out a large number of studies and experiments. The temperature control subsystem based on the fuzzy PID algorithm by Lu Yan et al. achieved a temperature control accuracy of ±0.1°C. Xiao Shan et al. designed a temperature control system for semiconductor lasers using a single-chip microcomputer, a thermistor, and a temperature control actuator TEC. The improved PID control algorithm shortened the adjustment time, and the overshoot decreased by 90%, and the control accuracy reached 0.05°C. Cui Guodong et al. developed a temperature control system for high-power semiconductor lasers, and its temperature control accuracy can reach ±0.1°C.

[0005] However, the cost of TEC packaging is now very high and it is not suitable for widely used in the chip temperature control of gas detection. Therefore, a unidirectional temperature control device and a detector without a TEC refrigeration circuit are provided to solve the above problems. Summary of the Utility Model

[0006] To solve the above technical problems, the utility model proposes a unidirectional temperature control device and a detector without a TEC refrigeration circuit, which can realize the cooperation between the temperature acquisition unit and the heating unit, and control the heating power by changing the input current of the heating unit, thereby realizing the precise temperature control of the laser. Compared with other temperature control technologies, its temperature control cost is low and the temperature control accuracy is high.

[0007] To achieve the above object, the present utility model provides a unidirectional temperature control device without a TEC refrigeration circuit, comprising:

[0008] A heat sink base having a heat insulation surface and a mounting surface at opposite ends, a laser being disposed on the mounting surface, the heat sink base including a heat sink base and a thermal resistance gasket, the thermal resistance gasket being laid and fixed at one end of the heat sink base to form the heat insulation surface of the heat sink base;

[0009] A temperature acquisition unit disposed on the mounting surface and close to the laser to acquire temperature information of the laser;

[0010] A heating unit disposed on the mounting surface and close to the laser, configured to heat the laser, the heating unit changing an input current according to the received temperature information to change an output temperature of the heating unit, so that the temperature of the laser is at a preset temperature.

[0011] Further, it further includes a contact electrode fixed on the mounting surface, the contact electrode being connected to the temperature acquisition unit.

[0012] Further, the temperature acquisition unit is fixed on the mounting surface, and the temperature acquisition unit is one of a thermistor and a temperature sensor.

[0013] Further, the preset temperature of the laser is higher than the ambient temperature.

[0014] Further, there are a pair of heating units, the pair of heating units being fixed on both sides of the laser, and the pair of heating units being connected in parallel.

[0015] Further, the distances between the pair of heating units and the laser are equal.

[0016] Further, the heating unit is a heating electrode fixed on the mounting surface.

[0017] A detector includes the above unidirectional temperature control device without a TEC refrigeration circuit.

[0018] Compared with the prior art, the present utility model has the following advantages and technical effects:

[0019] 1. The temperature acquisition unit cooperates with the heating unit to precisely control the temperature of the laser by changing the input current of the heating unit to control the heating power. Compared with other temperature control technologies, its temperature control cost is low and the temperature control accuracy is high.

[0020] 2. The processing cost is low, the volume is small, the weight is light, the material limitation is small, it can ensure a stable heat dissipation effect, ensure the long-term stability and uniformity of the laser during use, and improve the service life of the laser. Brief Description of the Drawings

[0021] The drawings forming a part of this application are used to provide a further understanding of this application. The schematic embodiments of this application and their descriptions are used to explain this application and do not constitute an improper limitation to this application. In the drawings:

[0022] Figure 1 is a perspective view of a unidirectional temperature control device;

[0023] Figure 2 is Figure 1 a top view of;

[0024] Figure 3 is Figure 1 a side view of;

[0025] Figure 4 is a temperature distribution diagram on the surface of the heat sink base.

[0026] Figure 5 is the temperature distribution in the active region of the laser core layer.

[0027] Figure 6 is a graph of the heating electrode power varying with the ambient temperature.

[0028] Figure 7 is the temperature control effect under the PID control algorithm;

[0029] Wherein, 1. Thermal resistance gasket; 2. Heat sink base; 3. Thermistor; 4. Laser; 5. Heating electrode; 6. Contact electrode. Detailed Description of the Preferred Embodiments

[0030] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0031] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below in conjunction with the drawings and specific embodiments.

[0032] Referring to Figure 1 - Figure 7, the present utility model provides a unidirectional temperature control device without a TEC refrigeration circuit, comprising: a heat sink base having a heat insulation surface and a mounting surface at opposite ends, and a laser 4 is disposed on the mounting surface; a temperature acquisition unit arranged on the mounting surface and close to the laser 4 to acquire the temperature information of the laser 4; a heating unit arranged on the mounting surface and close to the laser 4, configured to heat the laser 4, and the heating unit changes the input current according to the received temperature information to change the output temperature of the heating unit, so that the temperature of the laser 4 is at a preset temperature.

[0033] Specifically, the heat sink base has two opposite end faces, one of which is a heat insulation surface for heat insulation, and the other is a mounting surface for arranging the temperature acquisition unit, the laser 4, and the heating unit, and the mounting surface can be located above the heat insulation surface.

[0034] Among them, the heating unit is close to the laser 4 to heat and raise the temperature of the laser 4, and the temperature acquisition unit is used to detect the temperature of the laser 4 in real time. When the temperature of the laser 4 detected by the temperature acquisition unit is greater than the preset temperature, the current input to the heating unit is reduced, so that the output temperature of the heating unit is lowered. When the temperature of the laser 4 detected by the temperature acquisition unit is less than the preset temperature, the current input to the heating unit is increased, so that the output temperature of the heating unit is raised.

[0035] Specifically, first set the operating temperature of the laser 4 to a value much higher than the ambient temperature, adjust the injected current amount on the heating unit through the PID algorithm, and monitor the operating temperature of the laser 4 through the temperature acquisition unit, so that the laser 4 can be quickly and stably within 0.1 °C of the set value under different ambient temperatures.

[0036] Preferably, the operating temperature is set to 60 °C.

[0037] In this embodiment, referring to Figure 1 、 Figure 3 , the heat sink base includes a heat sink base 2 and a thermal resistance gasket 1, and the thermal resistance gasket 1 is laid and fixed at one end of the heat sink base 2 to form the heat insulation surface of the heat sink base.

[0038] Among them, the thermal resistance gasket 1 is used to prevent heat conduction at the bottom of the heat sink base 2.

[0039] Among them, it is adhered to the lower part of the heat sink base 2 by glue to prevent heat conduction, and its heat resistance ability can be changed by adjusting its thickness.

[0040] Among them, the thermal resistance gasket 1 is a high thermal resistance gasket, and the thermal conductivity of the thermal resistance gasket 1 is lower than 10 W / (m·K).

[0041] In this embodiment, referring to Figure 1 、 Figure 2, further comprising a contact electrode 6, fixed on the mounting surface, and the contact electrode 6 is connected to the temperature acquisition unit.

[0042] Among them, the relative positions of the thermistor 3, the laser 4, the heating electrode 5, and the contact electrode 6 arranged on the heat sink base 2 can be adjusted arbitrarily within the allowable range of the thin film circuit processing technology to meet different requirements.

[0043] Specifically, the contact electrode 6 is arranged on the mounting surface, and it is used to bond a gold wire to connect with the thermistor or the temperature sensor to achieve circuit control.

[0044] In this embodiment, referring to Figure 1 、 Figure 2 , the temperature acquisition unit is fixed on the mounting surface, and the temperature acquisition unit is one of the thermistor 3 and the temperature sensor.

[0045] Specifically, the thermistor 3 or other components that can be used to detect the temperature of the laser 4 are arranged on the mounting surface and close to the laser 4. The thermistor 3 can be set on one side of the laser 4 and matched with the laser 4, and the thermistor 3 is located between a pair of heating units.

[0046] Preferably, the thermistor 3 is the 3VH series of thin-film thermistors of Mitsubishi Corporation. It is an ultra-small thin-film thermistor.

[0047] Among them, the fixing methods of the thermistor 3 and the laser 4 to the mounting surface are preferably but not limited to soldering with gold-tin solder.

[0048] In this embodiment, the preset temperature of the laser 4 is higher than the ambient temperature.

[0049] In this embodiment, referring to Figure 1 、 Figure 2 , there are a pair of heating units. The pair of heating units are fixed on both sides of the laser 4, and the pair of heating units are connected in parallel.

[0050] Specifically, heating units are respectively arranged on both sides of the laser 4. The pair of heating units work simultaneously and have the same working power to provide the same heating temperature to both sides of the laser 4 to ensure uniform heating on both sides of the laser 4.

[0051] In this embodiment, referring to Figure 1 、 Figure 2 , the distances between the pair of heating units and the laser 4 are equal.

[0052] Specifically, the pair of heating units are arranged on both sides of the laser 4, and the distances between the two heating units and the laser 4 are equal to ensure that the heat provided by the two heating units to both sides of the laser 4 is equal. And by changing the relative distance between the heating unit and the laser 4, the temperature rise amount of the laser 4 and the temperature acquisition unit can be controlled.

[0053] In this embodiment, with reference to Figure 1 and Figure 2 , the heating unit is a heating electrode 5 fixed on the mounting surface.

[0054] Specifically, by inputting current to the heating electrode 5, the output temperature of the heating electrode 5 can be changed by adjusting the magnitude of the input current.

[0055] A detector includes the above-mentioned one-way temperature control device without a TEC refrigeration circuit.

[0056] Specifically, the detector can be a gas detector, that is, the gas detector is internally provided with a one-way temperature control device without a TEC refrigeration circuit to ensure that the output wavelength matches the absorption peak of the gas.

[0057] Alternatively, it can be other detection devices for outputting a specific wavelength, and at the same time, a one-way temperature control device without a TEC refrigeration circuit is built-in to achieve precise temperature control of the built-in laser 4. Compared with other temperature control technologies, its temperature control cost is low and the temperature control accuracy is high.

[0058] In a specific embodiment of the present invention, the thickness of the thermal resistance gasket 1 is 200 μm, the area is 1 mm × 1 mm, the thermal conductivity is 1.5 W / (m·K), and it is adhered to the bottom of the heat sink base 2 by glue. The substrate material of the heat sink base 2 is AlN, the thickness is 420 μm, the area is 1 mm × 1 mm, and both sides are metallized. The front side is gold-tin, which is used for gold-tin soldering the thermistor 3 and the heating electrode 5. The thermistor 3 is the 3VH series of thin-film thermistors of Mitsubishi Corporation, with a size of 0.32 mm × 0.32 mm and a thickness of 0.2 mm, and is bonded to the contact electrode 6. The resistance value of a single heating electrode 5 is 40 Ω, and it is distributed on both sides of the laser 4 in a parallel connection manner. The contact electrode 6 is Au and is arranged on the mounting surface at a certain interval.

[0059] Among them, through the above-built structural model, the temperature at different positions can be calculated under the thermal conductivity of different materials. Based on the heat conduction and finite element methods, ignoring the heat transfer mode of thermal radiation, the specific heat conduction principle of the present invention is as follows:

[0060]

[0061] Among them, T is the temperature, t is the time, x, y, z are the spatial coordinates; K is the material thermal conductivity; ρ and C are respectively the density and specific heat capacity of the semiconductor material; Q represents the heat power per unit volume of the heat source.

[0062] Among them, the internal heat source of the laser 4 is divided into two parts: the waveguide and the core layer. The external heating electrode 5 is two 40 Ω square resistances in parallel, and its heating power can be adjusted by current.

[0063] Refer to Figure 4 , the thermal conductivity of each material is determined in the COMSOL model to obtain the two-dimensional temperature distribution diagram on the heat sink surface.

[0064] Refer to Figure 5 , when the ambient temperature changes from -20°C to 45°C, by scanning the power value of the heating electrode 5 and monitoring that the temperature value at the thermistor 3 remains unchanged, the dependence relationship between the ambient temperature and the heating power is obtained. At this time, the core layer temperature is as Figure 6 shown.

[0065] Among them, under normal circumstances, the thermistor 3 does not monitor the true temperature of the core layer. The increase in the temperatures of both is closely related to the thermal resistance. The expression for the increase in temperature is as follows:

[0066] ΔT r =R 1 ·P 1 +R 2 ·P 2 +R 3 ·P 3

[0067] ΔT x =R 1 ·P 1 +R 2 ·P 2 +R 3 ·P 3

[0068] ΔT = ΔT x -ΔT r

[0069] Among them, R 1 , R 2 , R 3 are respectively the thermal resistances of the three heat sources to the thermistor 3, R 1 ′, R 2 ′, R 3 ′ are respectively the thermal resistances of the three heat sources to the core layer of the laser 4, and ΔT is the temperature difference between the temperature of the thermistor 3 and the temperature of the core layer of the laser 4. If the size of the heat source changes, this difference will change with the change of the thermal power per unit volume of the heat source.

[0070] Refer to Table 1. Assuming that the ambient temperature remains unchanged and the thermal power of the heating electrode 5 changes from 0 - 450 mW, at this time, the temperatures of the thermistor 3 and the core layer respectively and the temperature difference between them can be obtained.

[0071] Table 1 Influence of Heating Power on Temperature Difference

[0072] Heating power / mW <![CDATA[Thermistor 3 monitoring point T r / ℃]]> <![CDATA[Core layer temperature T x / ℃]]> <![CDATA[T x _T r / ℃]]> 0 50.73248246251194 54.73814984740051 4.0057 50 57.92709716527122 61.94011713478858 4.0130 100 65.12498098308328 69.14235908678495 4.0174 150 72.32656228199988 76.34819007000016 4.0216 200 79.53203015647017 83.55777711291523 4.0257 250 86.74157649420084 90.77128478222767 4.0297 300 93.95539482104152 97.9888743096082 4.0335 350 101.1736789711648 105.21072269932802 4.0370 400 108.39662092220033 112.4369984463898 4.0404 450 115.62440923588235 119.66793765195564 4.0435

[0073] Referring to Table 2, assuming that the heating power of the heating electrode 5 is determined and the ambient temperature is changed. Similarly, the temperatures of the thermistor 3 and the core layer and the temperature difference between them can also be obtained.

[0074] Table 2 Influence of Ambient Temperature on Temperature Difference

[0075] Ambient temperature / °C <![CDATA[Thermistor 3 monitoring point T r / ℃]]> <![CDATA[Core layer temperature T x / ℃]]> <![CDATA[T x _T r / ℃]]> -5 29.511676489113086 33.5427738542985 4.0311 5 39.52160568883767 43.56694159144848 4.0453 15 49.53138728057269 53.58899978473676 4.0576 25 59.54637058866649 63.628137634674374 4.0818 35 69.55903883564866 73.65870187402976 4.0997 45 79.57233209093101 83.69068345920044 4.1184 55 89.58626179584894 93.72409757234601 4.1378

[0076] From the temperature values monitored in Table 1 and Table 2, it can be seen that the change value of the temperature difference between the core layer temperature and the thermistor 3 temperature of the one-way temperature control device without a TEC refrigeration circuit is no more than 0.2 °C when the ambient temperature is -5 - 55 °C and the heating power is 0 - 450 mW.

[0077] In addition, referring to Figure 7 , by actually controlling the input current to the heating electrode 5 through the PID algorithm, the temperature can be quickly stabilized within ±0.1 °C of the set value in the range of -10 °C - 55 °C.

[0078] To sum up, first, based on the theoretical research of the thermal effect, a thermal model of the semiconductor detector with a heat sink structure was established using the finite element method (FEM). By optimizing the thickness and material of the thermal resistance gasket 1, the relative positions of the devices on the heat sink surface, and simultaneously adjusting the injection current of the heating electrode 5, the device operates at 60 °C. Finally, the scheme was tested, and the input current to the heating electrode 5 was controlled in two ways: the PID algorithm and segmented scanning. Eventually, the laser 4 can be quickly stabilized within ±0.1 °C of the set value in the range of -10 - 55 °C.

[0079] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in the present application should be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A one-way temperature control device without a TEC refrigeration circuit, characterized in that: include: A heat sink base having a heat insulation surface and a mounting surface located at two opposite ends, a laser (4) being arranged on the mounting surface, the heat sink base comprising a heat sink base (2) and a thermal resistance gasket (1), the thermal resistance gasket (1) being laid and fixed on one end of the heat sink base (2) to form a heat insulation surface of the heat sink base; A temperature acquisition unit is arranged on the mounting surface and close to the laser (4) to acquire temperature information of the laser (4); A heating unit is arranged on the mounting surface and close to the laser (4), and is configured to heat the laser (4). The heating unit changes an input current according to the received temperature information to change an output temperature of the heating unit so that the temperature of the laser (4) is at a preset temperature.

2. The one-way temperature control device without TEC refrigeration circuit according to claim 1, characterized in that: It also comprises a contact electrode (6) fixed on the mounting surface, and the contact electrode (6) is connected to the temperature acquisition unit.

3. The one-way temperature control device without TEC refrigeration circuit according to claim 1, characterized in that: The temperature acquisition unit is fixed on the mounting surface, and the temperature acquisition unit is one of a thermistor (3) and a temperature sensor.

4. The one-way temperature control device without TEC refrigeration circuit according to claim 1, characterized in that: The preset temperature of the laser (4) is higher than the ambient temperature.

5. The one-way temperature control device without TEC refrigeration circuit according to claim 1, characterized in that: A pair of the heating units is provided, the pair of the heating units is fixed on both sides of the laser (4), and the pair of the heating units is connected in parallel.

6. The one-way temperature control device without TEC refrigeration circuit according to claim 5, characterized in that: The distances between the pair of heating units and the laser (4) are equal.

7. The one-way temperature control device of the TEC-free refrigeration circuit according to claim 1 or 5, characterized in that: The heating unit is a heating electrode (5) fixed on the mounting surface.

8. A detector, characterized in that: A one-way temperature control device comprising a TEC-free refrigeration circuit as described in any one of claims 1 to 7.

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