Laser wavelength control method, device and system

Abstract

Embodiments of the present invention disclose a method, device, and system for controlling the wavelength of a laser. The method includes: generating a real-time temperature voltage in a preset first amplifier based on the real-time temperature output by the laser; generating an error-proportional voltage in a preset second amplifier based on a target temperature voltage and the real-time temperature voltage; wherein the target temperature voltage is the voltage corresponding to the temperature at which the laser outputs a preset wavelength; and adjusting the real-time temperature to the target temperature based on the error-proportional voltage to control the laser to stably output the preset wavelength. This method not only achieves a fast and highly accurate response to stabilize the laser's wavelength, but also provides a low-cost solution.

Description

Technical Field

[0001] The present invention relates to the technical field of laser wavelength control, and in particular to a method, device and system for controlling laser wavelength. Background Art

[0002] Since the advent of lasers, laser technology has played an increasingly important role in cutting-edge industrial equipment with its high sensitivity, high precision and non-contact characteristics. A frequency-stable laser source is a necessary guarantee for obtaining ultra-precision measurement accuracy. Since the wavelength of fiber lasers is greatly affected by temperature, different lasers have different wavelength drifts. The wavelength drift of the laser will affect the application effect of the laser during use, especially in some application environments that require stable laser wavelengths. The wavelength drift of the laser will seriously lead to a decrease in the efficiency of the laser pump tube and damage other optical components.

[0003] At present, there are two methods to control the wavelength of the laser. The first is to control the laser wavelength by controlling the laser resonant cavity through piezoelectric ceramics. Although this method can control the change of the laser cavity length within a certain range and make the frequency of the laser output uniform and stable, this control method has the displacement hysteresis nonlinearity and creep effect of the piezoelectric ceramics, which greatly affects its scanning accuracy and requires precise control of the scanning displacement of the piezoelectric ceramics. Moreover, the driving voltage of the piezoelectric ceramic device is relatively high and the step size is very small. Due to the influence of the power supply, it is difficult to control in actual operation, which can easily lead to unstable wavelength control. The second is to control the wavelength of the laser by temperature regulation. However, this method cannot accurately control the heating and cooling current of the laser, resulting in the inability to accurately control the wavelength of the laser. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method, device and system for controlling the wavelength of a laser, aiming to solve the technical problem in the prior art that the wavelength of the laser cannot be accurately and stably controlled.

[0005] In a first aspect, an embodiment of the present invention provides a method for controlling a laser wavelength, comprising:

[0006] generating a real-time temperature voltage in a preset first amplifier according to the real-time temperature output by the laser;

[0007] An error proportional voltage is generated in a preset second amplifier according to a target temperature voltage and the real-time temperature voltage; wherein the target temperature voltage is a voltage at a temperature corresponding to a preset wavelength output by the laser;

[0008] The real-time temperature is adjusted to a target temperature according to the error proportional voltage, so as to control the laser to stably output the preset wavelength.

[0009] In a second aspect, an embodiment of the present invention provides a laser wavelength control device, comprising:

[0010] A first generating unit, configured to generate a real-time temperature voltage in a preset first amplifier according to the real-time temperature output by the laser;

[0011] A second generating unit is configured to generate an error proportional voltage in a preset second amplifier according to a target temperature voltage and the real-time temperature voltage; wherein the target temperature voltage is a voltage at a temperature corresponding to a preset wavelength output by the laser;

[0012] The first regulating unit is configured to regulate the real-time temperature to a target temperature according to the error proportional voltage, so as to control the laser to stably output the preset wavelength.

[0013] In a third aspect, an embodiment of the present invention further provides a laser wavelength control system, which includes: a laser and a controller, wherein the controller executes the laser wavelength control method described in the first aspect.

[0014] Embodiments of the present invention provide a method, device, and system for controlling the wavelength of a laser. This method uses the real-time temperature of the laser output to generate a voltage corresponding to that temperature in an amplifier. Based on this voltage and a voltage corresponding to a set temperature, another amplifier generates an error-proportional voltage. This error-proportional voltage is used to adjust the real-time temperature of the laser to stabilize it at a preset temperature, thereby ensuring that the laser outputs a stable preset wavelength. This method not only achieves a fast and highly accurate response to stabilize the laser's wavelength, but also offers a low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0016] Figure 1 A schematic diagram of the structure of a laser wavelength control system provided by an embodiment of the present invention;

[0017] Figure 2 A schematic flow chart of a method for controlling laser wavelength provided in an embodiment of the present invention;

[0018] Figure 3 A schematic flow chart of a method for controlling laser wavelength according to an embodiment of the present invention;

[0019] Figure 4 A circuit diagram of the first amplifier in the laser wavelength control method provided by an embodiment of the present invention;

[0020] Figure 5 A circuit diagram of the first amplifier in the laser wavelength control method provided by an embodiment of the present invention;

[0021] Figure 6 Another schematic flow chart of a method for controlling laser wavelength according to an embodiment of the present invention;

[0022] Figure 7 Another schematic flow chart of a method for controlling laser wavelength according to an embodiment of the present invention;

[0023] Figure 8 Another schematic flow chart of a method for controlling laser wavelength according to an embodiment of the present invention;

[0024] Figure 9 A schematic block diagram of a control circuit in a method for controlling laser wavelength according to an embodiment of the present invention;

[0025] Figure 10 A circuit schematic diagram of a control circuit in a method for controlling laser wavelength provided by an embodiment of the present invention;

[0026] Figure 11 A schematic block diagram of a laser wavelength control device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0028] It will be understood that when used in this specification and the appended claims, the terms “comprises” and “comprising” indicate the presence of described features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0029] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the present invention. As used in the specification and appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0030] It should be further understood that the term "and / or" used in the present description and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0031] Embodiments of the present invention provide a method, device, and control system for controlling the wavelength of a laser.

[0032] To facilitate understanding, the laser wavelength control system is first introduced, and then the laser wavelength control method and device are introduced in detail based on this system.

[0033] See also Figure 1 , Figure 1 This is a schematic diagram of the structure of a laser wavelength control system provided in an embodiment of the present invention. The system includes a laser 11 and a controller 12, wherein the laser 11 is connected to the controller 12. The controller executes the laser wavelength control method provided in an embodiment of the present application to control the wavelength of the laser 11. The controller 12 can be a single-chip microcomputer.

[0034] After the system is started, the controller executes the laser wavelength control method provided in this embodiment to control the laser wavelength. Figure 2 , Figure 2 A schematic flow chart of a method for controlling laser wavelength provided in an embodiment of the present invention.

[0035] like Figure 2 As shown, the method includes steps S110 to S130.

[0036] S110 , generating a real-time temperature voltage in a preset first amplifier according to the real-time temperature output by the laser.

[0037] In this embodiment, there is a one-to-one correspondence between the wavelength of the laser, the temperature corresponding to the wavelength, and the voltage value corresponding to the temperature. The real-time temperature is the temperature of the laser in its current state. The first amplifier is used to convert the real-time temperature output by the laser into a real-time temperature voltage, i.e., the voltage is proportional to the real-time temperature. The real-time temperature is input through the first input terminal of the first amplifier, and 1 / 2 of Vref is input through the second input terminal of the first amplifier. The output terminal of the first amplifier can output the real-time temperature voltage.

[0038] In another embodiment, Figure 3 As shown, step S110 includes sub-steps S111 and S112.

[0039] S111, obtaining the real-time temperature according to a preset thermistor;

[0040] S112 . Perform a linear operation on the real-time temperature using the first amplifier to obtain a real-time temperature voltage.

[0041] In this embodiment, the thermistor can be close to the laser and can obtain the real-time temperature of the laser. After obtaining the real-time temperature of the laser, the thermistor inputs its temperature signal into the first input terminal of the first amplifier to obtain the real-time temperature voltage. The voltage input to the first amplifier is a function of the temperature of the thermistor. The circuit diagram is as shown below. Figure 4 As shown, the first amplifier is amplifier U1, the inverting input terminal of amplifier U1 is connected to half of the reference voltage Vref, the non-inverting input terminal is grounded through the thermistor and the resistor Rth respectively, and is connected to the output terminal OUT1 of the amplifier U1 through the resistor Rf. The formula for the voltage Vout1 output by the output terminal of the amplifier U1 is:

[0042]

[0043] Where Rth is the thermistor resistance and Vref is the reference voltage.

[0044] S120 , generating an error proportional voltage in a preset second amplifier according to a target temperature voltage and the real-time temperature voltage; wherein the target temperature voltage is a voltage at a temperature corresponding to a preset wavelength output by the laser.

[0045] Specifically, after the output end of the first amplifier outputs the real-time temperature voltage, the real-time temperature voltage and the target temperature voltage can be input into the first input end and the second input end of the second amplifier respectively to obtain the error proportional voltage. The error proportional voltage is a voltage used to heat or cool the laser. The error proportional voltage is calculated in the second amplifier by combining the real-time temperature voltage and the target temperature voltage. The output of the second amplifier is mainly used for temperature compensation of the first amplifier. The frequency response of the compensation is determined by the compensation network. The circuit diagram is shown in FIG. Figure 5 As shown, the second amplifier is amplifier U2, and the inverting input terminal of amplifier U2 is connected to the non-inverting input terminal of amplifier U2 through resistor R3 and connected to the output terminal of the first amplifier, and connected to the output terminal of amplifier U2 through resistor R4. The formula for the voltage Vout2 output by the output terminal of amplifier U2 is:

[0046]

[0047] Wherein: Z1 is the impedance of resistor R3, Z2 is the impedance of resistor R4, and Vtemp is the target temperature voltage.

[0048] S130 , adjusting the real-time temperature to a target temperature according to the error proportional voltage, so as to control the laser to stably output the preset wavelength.

[0049] In this embodiment, a TEC (Thermo Electric Cooler) is installed on the laser to monitor the laser's slight temperature changes. By heating or cooling the TEC, the laser's temperature can be controlled. Heating or cooling the TEC is controlled by simply controlling the current flowing into the TEC's terminals. A TEC consists of pairs (groups) of P-type and N-type electrodes connected by electrodes and sandwiched between two ceramic electrodes. When current flows through the TEC, the heat generated by the current is transferred from one side of the TEC to the other, achieving heating or cooling of the TEC.

[0050] Specifically, the error proportional voltage is calculated in the second amplifier through the voltage Vout1 output from the output end of the first amplifier and the target temperature voltage Vset. When Vout1 is not equal to Vset, it indicates that the temperature of the controlled laser has not yet reached the set target temperature. The error proportional voltage can be greater than 0 or less than 0. At this time, it is necessary to continue to change the direction and magnitude of the current at both ends of the TEC in the laser so that the laser reaches the target temperature, thereby enabling the laser to stably output the preset wavelength; when Vout1 is equal to Vset, the error proportional voltage is equal to 0, which indicates that the real-time temperature of the controlled laser is equal to the target temperature.

[0051] Furthermore, the TEC's real-time temperature can be adjusted via two sets of MOSFET drivers to control the TEC's heating or cooling. One set of drivers outputs a PWM amplifier, while the other outputs a high-gain linear amplifier. Each amplifier has a pair of outputs that drive the internal MOSFET gates, which in turn power the TEC, thereby controlling the TEC's heating or cooling. A comparator can also be placed between the two sets of MOSFET drivers to output a control signal to adjust the real-time temperature and thus the TEC's current direction and magnitude.

[0052] In another embodiment, Figure 6 As shown, step S130 includes sub-steps S210 and S220.

[0053] S210, performing high voltage protection on the TEC according to the center voltage, output voltage, and feedback voltage of the TEC in the laser;

[0054] S220 : Perform overcurrent protection on the TEC according to the central voltage and a voltage corresponding to an actual current of the TEC.

[0055] In an embodiment of the present invention, a voltage across the TEC (electrode-transmitter) is generated using a center voltage, an output voltage, and a feedback voltage. This voltage is proportional to the voltage across the TEC and provides high-voltage protection for the TEC. The output voltage is the voltage across the first terminal of the TEC, the feedback voltage is the voltage across the second terminal of the TEC, and the center voltage of the TEC corresponds to the TEC's 0V voltage. This center voltage can be 1.25V. The TEC voltage, Vtec, is calculated as: Vtec = 1.25 + 0.25 * (TEC output voltage - TEC feedback voltage).

[0056] At the same time, the voltage corresponding to the center voltage and the actual TEC current can also generate a simulated TEC current, namely the TEC current. This current is proportional to the actual current Itec flowing through the TEC. In this case, the center voltage is the voltage corresponding to a TEC current of 0A. The TEC current calculation formula is: Vset = 1.25V - Itec * R, where Vset is the voltage corresponding to the TEC current and R is the resistance at the actual current Itec on the TEC.

[0057] In another embodiment, Figure 7 As shown, step S210 also includes step S210a before step S210.

[0058] S210a, generating the output voltage and the feedback voltage according to the error proportional voltage and the operating voltages at both ends of the TEC in the laser.

[0059] Specifically, the voltage across the TEC is monitored through the feedback end and the output end of the TEC. The feedback end of the TEC is the second end of the TEC, and the output end of the TEC is the first end of the TEC. The operating voltage across the TEC is the same, but the operating current across the TEC is different, and their working methods are also different.

[0060] In another embodiment, Figure 8 As shown, step S210a includes sub-steps S210a1 and S210a2.

[0061] S210a1, generating the output voltage according to the error proportional voltage and the operating voltages at both ends of the TEC in the laser;

[0062] S210a2: Generate the feedback voltage according to the error proportional voltage and the output voltage.

[0063] In the embodiment of the present invention, the mathematical expressions of the output voltage and the feedback voltage are:

[0064] TEC output voltage = VB - 40 * (Vout2 - 1.25V)

[0065] TEC feedback voltage = TEC output voltage + 5 (Vout2 - 1.25V)

[0066] Among them: when the operating voltage across the TEC is less than 4.0V, VB = 1.5V; when the operating voltage across the TEC is greater than 4.0V, VB = 2.5V.

[0067] In addition, when the laser wavelength control circuit reaches a stable state, the output Vout2 of the amplifier U2 reaches the target setting value, and the control circuit automatically outputs a hysteresis voltage between 1.45V and 1.55. If it is lower than 1.45 or higher than 1.55, it will automatically control the TEC heating or cooling.

[0068] At the same time, to ensure that the TEC's heating or cooling operation is within the normal operating range, the heating or cooling voltage value of the TEC needs to be limited. When the heating current flows to the TEC, the internal current sink connected to the voltage limiting voltage will absorb the current, which will just reduce the TEC's limiting voltage. When the cooling current drives the TEC, the current sink is ineffective, so the heating voltage value is always lower than the cooling voltage value. Specifically, when the TEC voltage Vtec is 2.5V, the maximum TEC voltage limit voltage does not exceed 1.2V. The maximum setting of the voltage corresponding to the TEC current must be greater than 1.3V to ensure that the TEC has an appropriate margin between heating and cooling.

[0069] In the laser wavelength control method provided in an embodiment of the present invention, there is a one-to-one correspondence between the laser wavelength, the temperature corresponding to the wavelength, and the voltage value corresponding to the temperature. After setting the laser wavelength, it is only necessary to set a voltage value externally for the device. Once the voltage is set, the laser temperature can be automatically monitored based on the voltage value and the monitored temperature value can be converted into a voltage value corresponding to the temperature. At the same time, it is compared with the externally set voltage value in real time. When the monitored temperature voltage is greater than the target temperature voltage, the TEC can be automatically cooled to achieve cooling of the laser; when the monitored temperature voltage is less than the target temperature value, the TEC can be automatically heated to achieve heating of the laser, thereby ensuring in real time that the externally set temperature and the temperature of the laser itself are consistent. In addition, with the corresponding relationship between temperature and wavelength, when the externally set temperature is consistent with the temperature of the laser itself, the temperature of the laser itself can be guaranteed to be stable, thereby indirectly ensuring the stability of the laser wavelength. Compared with software-controlled laser wavelength, the laser wavelength control method of the present invention has low cost, fast response speed for stabilizing the wavelength, and high precision for stabilizing the wavelength. Furthermore, in order to protect the TEC and prevent damage to the TEC caused by excessive heating current, a voltage monitor and a current monitor are used to limit the current and voltage during TEC heating and cooling, thereby ensuring that the device operates within a normal current range.

[0070] The embodiment of the present invention also provides a control circuit for realizing a method for controlling the laser wavelength. Figure 9 , Figure 9 Schematic block diagram of the control circuit in the laser wavelength control method provided by the embodiment of the present invention. Figure 9 As shown, a laser wavelength control circuit includes:

[0071] TEC, the TEC is connected to the laser and is used to heat or cool the laser to control the wavelength of the laser;

[0072] A temperature monitoring unit 10 is connected to the laser and is used to monitor the real-time temperature of the laser;

[0073] A PID control unit 20 , connected to the temperature monitoring unit 10 and used to control the current direction and current magnitude of the TEC;

[0074] a first comparing unit 30, wherein a first input terminal of the first comparing unit 30 is connected to the PID control unit 20;

[0075] a second comparing unit 40, wherein a first output terminal of the second comparing unit 40 is connected to a first input terminal of the first comparing unit 30 and the PID control unit 20, respectively; a second output terminal of the second comparing unit 40 is connected to a second input terminal of the first comparing unit 30 and the PID control unit 20, respectively; and a second input terminal thereof is input with a TEC current;

[0076] a first switch unit 50 , wherein the first switch unit 50 is connected to the output terminal of the first comparison unit 30 and the second terminal of the TEC, and is connected to an input voltage Vin;

[0077] The second switch unit 60 is connected to the first end of the TEC and the first input end of the second comparison unit 40 respectively, and is connected to the input voltage Vin.

[0078] Among them, the PID control unit 20 generates a voltage corresponding to the real-time temperature based on the real-time temperature monitored by the temperature monitoring unit 10, and generates an error proportional voltage based on the voltage and the target temperature voltage Vtemp corresponding to the preset temperature of the laser. The first comparison unit 30 and the second comparison unit 40 control the conduction and shutdown of the first switch unit 50 and the second switch unit 60 through the error proportional voltage, thereby controlling the current direction and size of the TEC to heat or cool the TEC, thereby stabilizing the wavelength of the laser.

[0079] Specifically, in this embodiment, the first end of the TEC is the positive electrode, and the second end is the negative electrode. When the current in the TEC flows from the first end to the second end, the first switch unit 50 is disconnected and the second switch unit 60 is connected, and the TEC heats the laser. When the current in the TEC flows from the second end to the first end, the first switch unit 50 is connected and the second switch unit 60 is disconnected, and the TEC cools the laser.

[0080] In an embodiment of the present invention, the wavelength of the laser, the temperature of the laser, and the voltage corresponding to the temperature have a one-to-one correspondence. Different wavelengths correspond to different temperatures. When the temperature of the laser changes, the wavelength of the laser will drift. Therefore, the present application controls the current direction and magnitude of the TEC by generating an error proportional voltage to heat or cool the TEC, thereby stabilizing the wavelength of the laser at a preset temperature.

[0081] In some embodiments, the temperature monitoring unit 10 includes a thermistor Rth. One end of the thermistor Rth is grounded, and the other end is connected to the PID control unit 20 and to a reference voltage Vref. Specifically, the laser diode, TEC, and thermistor Rth are packaged in a laser diode module. The TEC heats or cools the laser diode. Similarly, the thermistor Rth monitors the real-time temperature of the laser diode.

[0082] The thermistor Rth may be a temperature resistor with a negative temperature coefficient (NTC) or a temperature resistor with a positive temperature coefficient (RTD). This is not specifically limited in this embodiment and may be selected based on specific practical applications.

[0083] In some embodiments, the PID control unit 20 includes a temperature voltage generating unit and an error proportional voltage generating unit; wherein the temperature voltage generating unit is connected to the temperature monitoring unit 10 and the error proportional voltage generating unit, respectively, and the error proportional voltage generating unit is connected to the first input terminal of the first comparison unit 30. Specifically, the temperature voltage generating unit is configured to receive the real-time temperature of the temperature monitoring unit 10 and convert the real-time temperature into a linear voltage that is proportional to the real-time temperature of the laser. After receiving the linear voltage, the error proportional voltage generating unit compares it with the target temperature voltage Vtemp corresponding to the preset wavelength of the laser to generate an error proportional voltage, thereby turning on and off the first switch unit 50 and the second switch unit 60, thereby heating or cooling the TEC and stabilizing the wavelength of the laser.

[0084] In some specific embodiments, such as Figure 4 As shown, the temperature voltage generating unit includes an amplifier U1 and a feedback resistor Rf; wherein, the positive input terminal of the amplifier U1 is connected to the temperature monitoring unit 10, and is connected to the reference voltage Vref, and is connected to the output terminal of the amplifier U1 through the feedback resistor Rf, the negative input terminal of the amplifier U1 is connected to half of the reference voltage Vref, and the output terminal of the amplifier U1 is connected to the error proportional voltage generating unit.

[0085] Specifically, in Figure 4 In the embodiment shown, the temperature voltage generating unit further includes a voltage divider circuit including resistors R1 and R2. The positive input terminal of the amplifier U1 is connected to the thermistor Rth through the resistor R1 and is connected to the reference voltage Vref through the resistor R2.

[0086] In some specific embodiments, such as Figure 5As shown, the error proportional voltage generating unit includes an amplifier U2 and a resistor R4; wherein, the positive input terminal of the amplifier U2 is connected to the output terminal of the amplifier U1, and is connected to the output terminal of the amplifier U2 through the resistor R4, the reverse input terminal of the amplifier U2 is connected to the target temperature voltage Vtemp of the laser, and the output terminal of the amplifier U2 is connected to the first input terminal of the first comparison unit 30.

[0087] Specifically, in Figure 5 In the embodiment shown, the positive input terminal of the amplifier U2 is connected to the output terminal of the amplifier U1 through the resistor R3. The target temperature voltage Vtemp is the voltage corresponding to the preset wavelength of the laser. The target temperature voltage Vtemp can be output through the DA input of the external microcontroller or through a digital potentiometer.

[0088] In some embodiments, as Figure 10 As shown, the first comparison unit 30 includes a comparator U7, and the second comparison unit 40 includes a comparator U10; wherein the positive input terminal of the comparator U7 is connected to the PID control unit 20 and the first output terminal of the comparator U10 respectively, and the negative input terminal is connected to the second output terminal of the comparator U10; the positive input terminal of the comparator U10 is connected to the second switch unit 60, and the negative input terminal inputs the TEC current; the first switch unit 50 includes a MOS transistor Q1, and the second switch unit 60 includes a MOS transistor Q2; wherein the gate of the MOS transistor Q1 is connected to the output terminal of the first comparison unit 30, the source is connected to the second terminal of the TEC, and the drain is connected to the input voltage Vin; the gate of the MOS transistor Q2 is connected to the input terminal of the second comparison unit 40, the source is connected to the input voltage Vin, and the drain is connected to the first terminal of the TEC.

[0089] exist Figure 10In the illustrated embodiment, MOS transistor Q1 is an N-type MOS transistor, and MOS transistor Q2 is a P-type MOS transistor. A body diode is connected between the source and drain of MOS transistors Q1 and Q2. The circuit also includes amplifiers U3 and U4. The non-inverting input of amplifier U3 is connected to the output of amplifier U2 via resistor R5, the inverting input is connected to the output of amplifier U3 via resistor R8, and is connected to a reference voltage Vref via resistor R9. The output of amplifier U3 is connected to the non-inverting input of amplifier U4 via resistor R7. The inverting input of amplifier U4 is connected to power supply voltage VDD, and the output is connected to the non-inverting input of comparator U7. Specifically, amplifier U3, resistors R8, and R9 form a negative feedback amplifier circuit, and amplifier U4, resistors R15, R16, R17, capacitors C1, C2, and C3 form a negative feedback amplifier circuit, thereby quickly stabilizing the laser wavelength and improving the accuracy of the stabilization of the laser wavelength.

[0090] In some embodiments, as Figure 10 As shown, the circuit also includes amplifiers U5 and U6. The non-inverting input of amplifier U5 is connected to the PID control unit 20 and the first input of the first comparison unit 30, respectively, and is connected to the reference voltage Vref via resistor R11. It is also connected to the output of amplifier U3 via resistors R12, R10, and R7, in sequence. Its inverting input is connected to the output of amplifier U5 via resistors R13 and R14, in sequence. The output of amplifier U5 outputs the TEC voltage. The non-inverting input of amplifier U6 is connected to the non-inverting input of comparator U10 and the gate of the MOS transistor, respectively. Its inverting input is connected to the inverting input of comparator U10 and the output of amplifier U6 via resistor R18, respectively. The output of amplifier U6 outputs the TEC current. Specifically, amplifier U5, resistors R13, and R14 form a negative feedback amplifier circuit for high-voltage protection of the TEC, while amplifier U6 and resistor R18 form a negative feedback amplifier circuit for overcurrent protection of the TEC.

[0091] exist Figure 10In the embodiment shown, the circuit further includes a switch S1, a comparator U9, a switch S2, an amplifier U8, and a NOT gate; wherein the first end of the switch S1 is connected to the first output end of the second comparison unit 40, the second end is connected to the power supply voltage VDD, and the third end is connected to the inverting input end of the amplifier U8; the non-inverting input end of the amplifier U8 inputs the TEC current, and the output end is respectively connected to the first input end of the PID control unit 20 and the first comparison unit 30; the first end of the switch S2 is connected to the second output end of the second comparison unit 40, and the second end is respectively connected to the non-inverting input end of the comparator U9, the PID control unit 20, the output end of the amplifier U8, and the first input end of the first comparison unit 30; the inverting input end of the comparator is connected to the power supply voltage VCC, and the output end is connected to the first input end of the NOT gate; the second input end of the NOT gate is connected to the enable signal, and the output end is connected to the second input end of the first comparison unit 30.

[0092] Specifically, when the first output end of the comparator U10 generates a cooling signal, the first end of the switch S1 is connected to the third end, the first end of the switch S2 is disconnected from the second end, the output end of the comparator U7 is at a high level, the MOS tube Q1 is turned on, and the MOS tube Q2 is not turned on. At this time, the current on the TEC flows from the second end to the first end, and the TEC starts the cooling mode; when the second output end of the comparator U10 generates a heating signal, the first end of the switch S1 is connected to the second end, the first end of the switch S2 is connected to the second end, the output end of the comparator U7 is at a low level, the MOS tube Q1 is not turned on, and the MOS tube Q2 is turned on. At this time, the current on the TEC flows from the first end to the second end, and the TEC starts the heating mode.

[0093] An embodiment of the present invention further provides a laser, which includes a laser body and the above-mentioned laser wavelength control circuit to lock the laser wavelength and ensure that the device operates within a normal current range.

[0094] See also Figure 11 , Figure 11 This is a block diagram of a laser wavelength control device according to an embodiment of the present invention. The control device can be run in a controller to control the wavelength of a laser connected to the controller to ensure that the laser wavelength can operate more accurately at a preset temperature.

[0095] Among them, such as Figure 11 As shown, the laser wavelength control device 100 includes: a first generating unit 110 , a second generating unit 120 and a first adjusting unit 130 .

[0096] The first generating unit 110 is configured to generate a real-time temperature voltage in a preset first amplifier according to the real-time temperature output by the laser.

[0097] The second generating unit 120 is configured to generate an error proportional voltage in a preset second amplifier according to a target temperature voltage and the real-time temperature voltage; wherein the target temperature voltage is a voltage at a temperature corresponding to a preset wavelength output by the laser.

[0098] The first adjusting unit 130 is configured to adjust the real-time temperature to a target temperature according to the error proportional voltage, so as to control the laser to stably output the preset wavelength.

[0099] In one embodiment, the first generating unit 110 includes: an acquiring unit and a linear operation unit.

[0100] The acquisition unit is used to acquire the real-time temperature according to a preset thermistor.

[0101] A linear operation unit is used to perform a linear operation on the real-time temperature according to the first amplifier to obtain a real-time temperature voltage.

[0102] In one embodiment, the laser wavelength control device 100 further includes: a high voltage protection unit and an overcurrent protection unit.

[0103] A high-voltage protection unit, configured to perform high-voltage protection on the TEC according to the center voltage, output voltage, and feedback voltage of the TEC in the laser;

[0104] An overcurrent protection unit is used to perform overcurrent protection on the TEC according to the central voltage and the voltage corresponding to the actual current of the TEC.

[0105] In one embodiment, the laser wavelength control device 100 further includes a third generating unit.

[0106] The third generating unit is configured to generate the output voltage and the feedback voltage according to the error proportional voltage and the operating voltages at both ends of the TEC in the laser.

[0107] In one embodiment, the third generating unit includes: a fourth generating unit and a fifth generating unit.

[0108] a fourth generating unit, configured to generate the output voltage according to the error proportional voltage and the operating voltage across the TEC in the laser;

[0109] A fifth generating unit is configured to generate the feedback voltage according to the error proportional voltage and the output voltage.

[0110] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described devices and units can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0111] The steps in the method of the embodiment of the present application can be adjusted in order, combined and deleted according to actual needs.

[0112] The units in the device of the embodiment of the present application can be merged, divided and deleted according to actual needs.

[0113] In addition, the functional units in the various embodiments of the present application may be integrated into a single processing unit, or each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0114] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and such modifications or substitutions are intended to be within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope of protection of the claims.

Claims

1. A method for controlling the wavelength of a laser, characterized in that: include: generating a real-time temperature voltage in a preset first amplifier according to the real-time temperature output by the laser; An error proportional voltage is generated in a preset second amplifier according to a target temperature voltage and the real-time temperature voltage; wherein the target temperature voltage is a voltage at a temperature corresponding to a preset wavelength output by the laser; adjusting the real-time temperature to a target temperature according to the error proportional voltage to control the laser to stably output the preset wavelength; The control circuit of the method comprises: TEC, the TEC is connected to the laser and is used to heat or cool the laser to control the wavelength of the laser; A temperature monitoring unit 10 is connected to the laser and is used to monitor the real-time temperature of the laser; A PID control unit 20 , connected to the temperature monitoring unit 10 and used to control the current direction and current magnitude of the TEC; a first comparing unit 30, wherein a first input terminal of the first comparing unit 30 is connected to the PID control unit 20; a second comparing unit 40, wherein a first output terminal of the second comparing unit 40 is connected to a first input terminal of the first comparing unit 30 and the PID control unit 20, respectively; a second output terminal of the second comparing unit 40 is connected to a second input terminal of the first comparing unit 30 and the PID control unit 20, respectively; and a second input terminal thereof is input with a TEC current; a first switch unit 50 , wherein the first switch unit 50 is connected to the output terminal of the first comparison unit 30 and the second terminal of the TEC, and is connected to an input voltage Vin; A second switch unit 60, the second switch unit 60 is connected to the first end of the TEC and the first input end of the second comparison unit 40 respectively, and is connected to the input voltage Vin; The first comparison unit 30 includes a comparator U7, and the second comparison unit 40 includes a comparator U10; wherein the positive input terminal of the comparator U7 is connected to the PID control unit 20 and the first output terminal of the comparator U10, respectively, and the negative input terminal is connected to the second output terminal of the comparator U10; the positive input terminal of the comparator U10 is connected to the second switching unit 60, and the negative input terminal inputs the TEC current; The circuit further includes a switch S1, a comparator U9, a switch S2, an amplifier U8, and a NOT gate; wherein the first end of the switch S1 is connected to the first output end of the comparator U10, the second end is connected to the power supply voltage VDD, and the third end is connected to the inverting input end of the amplifier U8; the non-inverting input end of the amplifier U8 inputs the TEC current, and the output end is respectively connected to the PID control unit and the first input end of the comparator U7; the first end of the switch S2 is connected to the second output end of the comparator U10, and the second end is respectively connected to the non-inverting input end of the comparator U9, the PID control unit, the output end of the amplifier U8, and the first input end of the comparator U7; the inverting input end of the comparator U9 is connected to the power supply voltage VCC, and the output end is connected to the first input end of the NOT gate; the second input end of the NOT gate is connected to the enable signal, and the output end is connected to the second input end of the comparator U7; The first output terminal of the comparator U10 generates a cooling signal, the first terminal of the switch S1 is connected to the third terminal, the first terminal of the switch S2 is disconnected from the second terminal, the output terminal of the comparator U7 is at a high level, the first switch unit is turned on, the second switch unit is turned off, the current on the TEC flows from the second terminal to the first terminal, and the TEC enters the cooling mode; The second output end of the comparator U10 generates a heating signal, the first end of the switch S1 is connected to the second end, the first end of the switch S2 is connected to the second end, the output end of the comparator U7 is at a low level, the first switch unit is not conducting, the second switch unit is conducting, the current on the TEC flows from the first end to the second end, and the TEC starts the heating mode.

2. The laser wavelength control method according to claim 1, characterized in that: Generating a voltage of the real-time temperature in a preset first amplifier according to the real-time temperature output by the laser comprises: Acquiring the real-time temperature according to a preset thermistor; A linear operation is performed on the real-time temperature using the first amplifier to obtain a real-time temperature voltage.

3. The laser wavelength control method according to claim 1, characterized in that: Generating an error proportional voltage in a preset second amplifier according to the target temperature voltage and the voltage of the real-time temperature includes: The real-time temperature voltage and the target temperature voltage are input into the first input terminal and the second input terminal of the second amplifier respectively to obtain the error proportional voltage.

4. The laser wavelength control method according to claim 1, characterized in that: Before adjusting the real-time temperature to the target temperature according to the error proportional voltage to control the laser to stably output the preset wavelength, the method further includes: Performing high voltage protection on the TEC according to the center voltage, output voltage and feedback voltage of the TEC in the laser; Overcurrent protection is performed on the TEC according to the central voltage and the voltage corresponding to the actual current of the TEC.

5. The laser wavelength control method according to claim 4, characterized in that: Before performing high voltage protection on the TEC according to the central voltage, output voltage and feedback voltage of the TEC in the laser, the method further includes: The output voltage and the feedback voltage are generated according to the error proportional voltage and the operating voltage across the TEC in the laser.

6. The laser wavelength control method according to claim 5, characterized in that: The step of generating the output voltage and the feedback voltage according to the error proportional voltage and the operating voltage across the TEC in the laser comprises: generating the output voltage according to the error proportional voltage and the operating voltage across the TEC in the laser; The feedback voltage is generated according to the error proportional voltage and the output voltage.

7. A laser wavelength control device, characterized in that: include: A first generating unit, configured to generate a real-time temperature voltage in a preset first amplifier according to the real-time temperature output by the laser; A second generating unit is configured to generate an error proportional voltage in a preset second amplifier according to a target temperature voltage and the real-time temperature voltage; wherein the target temperature voltage is a voltage at a temperature corresponding to a preset wavelength output by the laser; a first regulating unit, configured to regulate the real-time temperature to a target temperature according to the error proportional voltage, so as to control the laser to stably output the preset wavelength; The circuit corresponding to the device includes: TEC, the TEC is connected to the laser and is used to heat or cool the laser to control the wavelength of the laser; A temperature monitoring unit 10 is connected to the laser and is used to monitor the real-time temperature of the laser; A PID control unit 20 , connected to the temperature monitoring unit 10 and used to control the current direction and current magnitude of the TEC; a first comparing unit 30, wherein a first input terminal of the first comparing unit 30 is connected to the PID control unit 20; a second comparing unit 40, wherein a first output terminal of the second comparing unit 40 is connected to a first input terminal of the first comparing unit 30 and the PID control unit 20, respectively; a second output terminal of the second comparing unit 40 is connected to a second input terminal of the first comparing unit 30 and the PID control unit 20, respectively; and a second input terminal thereof is input with a TEC current; a first switch unit 50 , wherein the first switch unit 50 is connected to the output terminal of the first comparison unit 30 and the second terminal of the TEC, and is connected to an input voltage Vin; A second switch unit 60, the second switch unit 60 is connected to the first end of the TEC and the first input end of the second comparison unit 40 respectively, and is connected to the input voltage Vin; The first comparison unit 30 includes a comparator U7, and the second comparison unit 40 includes a comparator U10; wherein the positive input terminal of the comparator U7 is connected to the PID control unit 20 and the first output terminal of the comparator U10, respectively, and the negative input terminal is connected to the second output terminal of the comparator U10; the positive input terminal of the comparator U10 is connected to the second switching unit 60, and the negative input terminal inputs the TEC current; The circuit further includes a switch S1, a comparator U9, a switch S2, an amplifier U8, and a NOT gate; wherein the first end of the switch S1 is connected to the first output end of the comparator U10, the second end is connected to the power supply voltage VDD, and the third end is connected to the inverting input end of the amplifier U8; the non-inverting input end of the amplifier U8 inputs the TEC current, and the output end is respectively connected to the PID control unit and the first input end of the comparator U7; the first end of the switch S2 is connected to the second output end of the comparator U10, and the second end is respectively connected to the non-inverting input end of the comparator U9, the PID control unit, the output end of the amplifier U8, and the first input end of the comparator U7; the inverting input end of the comparator U9 is connected to the power supply voltage VCC, and the output end is connected to the first input end of the NOT gate; the second input end of the NOT gate is connected to the enable signal, and the output end is connected to the second input end of the comparator U7; The first output terminal of the comparator U10 generates a cooling signal, the first terminal of the switch S1 is connected to the third terminal, the first terminal of the switch S2 is disconnected from the second terminal, the output terminal of the comparator U7 is at a high level, the first switch unit is turned on, the second switch unit is turned off, the current on the TEC flows from the second terminal to the first terminal, and the TEC enters the cooling mode; The second output end of the comparator U10 generates a heating signal, the first end of the switch S1 is connected to the second end, the first end of the switch S2 is connected to the second end, the output end of the comparator U7 is at a low level, the first switch unit is not conducting, the second switch unit is conducting, the current on the TEC flows from the first end to the second end, and the TEC starts the heating mode.

8. The laser wavelength control device according to claim 7, characterized in that: The first generating unit includes: an acquisition unit, configured to acquire the real-time temperature according to a preset thermistor; A linear operation unit is used to perform a linear operation on the real-time temperature according to the first amplifier to obtain a real-time temperature voltage.

9. The laser wavelength control device according to claim 7, characterized in that: The device further comprises: A high-voltage protection unit, configured to perform high-voltage protection on the TEC according to the center voltage, output voltage, and feedback voltage of the TEC in the laser; An overcurrent protection unit is used to perform overcurrent protection on the TEC according to the central voltage and the voltage corresponding to the actual current of the TEC.

10. A laser wavelength control system, characterized in that: include: A laser and a controller, wherein the controller executes the laser wavelength control method according to any one of claims 1 to 6.

Images