Miniature seed light source module structure for laser

Abstract

The utility model discloses a miniature seed light source module structure for a laser, which belongs to the field of lasers and is miniaturized in size and power, has an active cooling function, is convenient to supply power and is favorable for being debugged and carried outside. The device mainly comprises a shell, a circuit board connected with a laser is arranged in the shell, the laser is connected with an optical fiber patch cord, and a charging port is formed in the shell; the circuit board comprises a laser TEC constant current circuit, a PI temperature control circuit and an over-temperature protection circuit, the laser TEC constant current circuit comprises an operational amplifier U1, a positive input end of the operational amplifier U1 is connected with a protection resistor R1, and an output end of the operational amplifier U1 is connected with a base electrode of a triode Q1 through a resistor R7. The miniature seed light source is mainly used for miniature seed light sources.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of laser, concretely, especially relates to a micro seed light source module structure for laser. BACKGROUND

[0002] The laser seed source is a device that provides an initial optical signal for a laser, and its core function is to guide the laser to produce a mode with high intensity and the same phase, and then amplify this mode and output it with high power.

[0003] The seed light source is the soul of the laser, and only a good seed source signal can produce a stable light source, which is of great significance in the fields of science and technology, medicine, and industry. For example, in laser communication, the frequency stability and spectral purity of the laser seed source can be used to achieve higher speed and safer data transmission; in laser ranging, the laser seed source can provide higher accuracy and shorter response time for the ranging signal.

[0004] The existing seed light source on the market includes a single-chip microcomputer, a laser driver circuit, a temperature control circuit, a heat dissipation part, a laser part, and an optical path part. To meet the stable output performance and improve the heat dissipation capacity, the modules are generally large in size. For example, a pulsed fiber laser and its control method are disclosed in publication No. CN103474869A. UTILITY MODEL CONTENT

[0005] The utility model aims to provide a micro seed light source module structure for laser, which is miniaturized in size, small in power, has an active cooling function, is convenient for power supply, and is beneficial for outdoor debugging and carrying.

[0006] The utility model is implemented through the following technical solutions:

[0007] A micro seed light source module structure for laser includes a shell, a circuit board connected with a laser in the shell, a laser connected with a fiber jumper, a charging port on the shell connected with a power module of the circuit board, and a switch on the shell connected with the circuit board. The circuit board includes a laser TEC constant current circuit, a PI temperature control circuit, and an over-temperature protection circuit. The laser TEC constant current circuit includes an operational amplifier U1, a protection resistor R1 connected with the positive input terminal of the operational amplifier U1, a base of a triode Q1 connected with the output terminal of the operational amplifier U1 through a resistor R7, an emitter of the triode Q1 connected with a resistor R8, the negative input terminal of the operational amplifier U1 connected with the resistor R8 through a protection resistor R6, and a filter capacitor C5 connected with the negative input terminal of the operational amplifier U1 and the output terminal of the operational amplifier U1.

[0008] Further, the charging port adopts a Type-C interface, and the fiber jumper is an FC / APC fiber tail fiber jumper.

[0009] Further, the PI temperature control circuit comprises a Wheatstone bridge, the Wheatstone bridge is connected with the positive input end of the operational amplifier U2 through the resistor R16, the Wheatstone bridge is connected with the negative input end of the operational amplifier U2 through the resistor R15, and the resistor R20 and the capacitor C13 are connected in series between the negative input end of the operational amplifier U2 and the output end of the operational amplifier U2.

[0010] Further, the over-temperature protection circuit comprises the operational amplifier U3 and the triode Q5, the positive input end of the operational amplifier U3 is connected with the protection circuit through the resistor R27, the negative input end of the operational amplifier U3 is connected with the thermal resistor RT of the laser through the resistor R26, the base of the triode Q5 is connected with the resistor R23 through the second filter circuit, and the emitter of the triode Q5 is connected with the B end of the common cathode diode D1.

[0011] Further, the protection circuit comprises the resistor R25 and the resistor R24 connected in series, and the positive input end of the operational amplifier U3 is connected between the resistor R25 and the resistor R24 through the resistor R27.

[0012] Further, the second filter circuit comprises the resistor R28 and the capacitor C15, and the resistor R28 and the capacitor C15 are connected in parallel and then connected between the base of the triode Q5 and the resistor R23.

[0013] Further, the positive input end of the operational amplifier U1 and the protection resistor R1 are further connected with the first filter circuit, the first filter circuit comprises the resistor R2 and the capacitor C3, and the resistor R2 and the capacitor C3 are connected in parallel and then connected between the positive input end of the operational amplifier U1 and the protection resistor R1.

[0014] Compared with the prior art, the utility model has the advantages of:

[0015] 1. The over-temperature protection circuit is fast in response to the over-temperature signal, generates the protection signal, and the later-stage triode circuit stores and maintains the signal for seconds, thereby reducing frequent over-temperature protection caused by high temperature of the laser for a long time.

[0016] 2. The PI temperature control circuit can obviously improve the steady-state error of the system, increase the phase lag, and increase the regulation time.

[0017] 3. The seed light source is small in size, simple in hardware circuit, realizes active cooling, is stable in light source output, is convenient in power supply, and is beneficial to carrying. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 It is the structural schematic diagram of the utility model;

[0019] Figure 2 It is the circuit principle diagram of the utility model;

[0020] Figure 3 is a circuit diagram of the TEC constant current circuit of the laser of the utility model;

[0021] Figure 4 is a circuit diagram of the PI temperature control circuit of the utility model;

[0022] Figure 5 is a circuit diagram of the over-temperature protection circuit of the utility model.

[0023] In the figure: 1, shell; 2, fiber jumper; 3, switch; 4, charging port. DETAILED DESCRIPTION

[0024] The utility model will be further described with reference to the drawings.

[0025] As Figure 1 - Figure 5 The utility model discloses a micro seed light source module structure for laser, including shell 1, the circuit board that is connected with laser is equipped in the shell 1, laser is connected with fiber jumper 2, is equipped with the charging port 4 on the shell 1, and the charging port 4 is connected with the power module of circuit board, and is equipped with the switch 3 that is connected with circuit board on the shell 1;Circuit board includes laser TEC constant current circuit, PI temperature control circuit and over-temperature protection circuit, laser TEC constant current circuit includes operational amplifier U1, and the positive input end of operational amplifier U1 is connected with protection resistance R1, and the output end of operational amplifier U1 is connected the base of triode Q1 through resistance R7, and the emitter of triode Q1 is connected resistance R8, and the negative input end of operational amplifier U1 is connected resistance R8 through protection resistance R6, and the negative input end of operational amplifier U1 and the output end of operational amplifier U1 are connected with filter capacitor C5;The charging port adopts Type-C interface;Fiber jumper 2 is FC / APC fiber tail fiber jumper.

[0026] When triode Q1 is turned on and forms current I, resistance R8 will produce voltage V=R8 *I, at this time voltage V enters operational amplifier U1 (use as comparator) after current limiting through protection resistance R6, compare the voltage V with the reference voltage that is set in advance, and operational amplifier U1 is turned off when voltage V is greater than reference voltage, and is turned on when voltage V is less than reference voltage, so that triode Q1 is regulated, and the current that flows through triode Q1 reaches the size of the expected design, and then constant current control is realized. The constant current circuit of TEC refrigeration is similar to the laser TEC constant current circuit, which will not be repeated here.

[0027] The PI temperature control circuit of the micro seed light source module structure for laser includes a Wheatstone bridge (consisting of resistors R9, R10, R13 and R14), the Wheatstone bridge is connected to the positive input terminal of the operational amplifier U2 through resistor R16, the Wheatstone bridge is connected to the negative input terminal of the operational amplifier U2 through resistor R15, resistor R20 and capacitor C13 are connected in series between the negative input terminal of the operational amplifier U2 and the output terminal of the operational amplifier U2; the over-temperature protection circuit includes an operational amplifier U3 and a transistor Q5, the positive input terminal of the operational amplifier U3 is connected to the protection circuit through resistor R27, the negative input terminal of the operational amplifier U3 is connected to the thermistor RT of the laser through resistor R26; the base of the transistor Q5 is connected to resistor R23 through filter circuit two, the emitter of the transistor Q5 is connected to the B terminal of the common cathode diode D1; the protection circuit includes resistor R25 and resistor R24 connected in series, the positive input terminal of the operational amplifier U3 is connected between resistor R25 and resistor R24 through resistor R27; filter circuit two includes resistor R28 and capacitor C15, resistor R28 and capacitor C15 are connected in parallel and then connected between the base of the transistor Q5 and resistor R23; filter circuit one is further connected between the positive input terminal of the operational amplifier U1 and the protection resistor R1, filter circuit one includes resistor R2 and capacitor C3 connected in parallel and connected between the positive input terminal of the operational amplifier U1 and the protection resistor R1, and the rest is the same as in embodiment 1.

[0028] The resistance value of the thermistor RT of the laser is about 10K at normal temperature (25℃), the resistance value decreases as the temperature rises, and the resistance value increases as the temperature decreases. The voltage at the position of the thermistor RT is (R9 / / RRT) / ((R9 / / RRT)+R10)*Vref, the value at this point decreases as the temperature of the laser rises, and vice versa. We only need to set the reference voltage of the other port of the operational amplifier U2 to complete the operation at the predetermined temperature, and the voltage is balanced at R13 / (R13+R14)*Vref. When the signal from the temperature of the laser is greater than the reference voltage, that is, the state does not need to be cooled, TEC_CTRL outputs low voltage and is less than the reference voltage, which means that cooling is needed, and TEC_CTRL outputs high. The whole circuit forms a PI regulator, and its output can be summarized as the following equation:

[0029]

[0030] Wherein, Vo is TEC_CTRL, Vi is RT, and Vref is the set reference voltage. The performance of the whole circuit can be adjusted by adjusting resistor R15, resistor R20 and capacitor C13.

[0031] After TEC_CTRL output high, will open control refrigeration MOS, with laser constant current circuit, the circuit will also enter constant current state.

[0032] Laser temperature signal represented by V is directly compared with the set threshold voltage for output, aiming to quickly form a protection signal, the default state of V RT is much greater than the set threshold voltage, TEC_P is low, and the corresponding TEC_PROTECTION is also low, that is, the protection circuit does not work. When V is greater than the set threshold voltage R24 / (R24+R25)*V reference, the operational amplifier U3 quickly flips to output high, at which time TEC_P and TEC_PROTECTION are both high, and the corresponding triode Q5 is turned on. TEC_P activates triode Q5 at the same time, and charges capacitor C15. When the TEC_P signal disappears temporarily, capacitor C15 begins to discharge, and its current is released to the ground through resistor R28. After calculation, the discharge process of capacitor C15 can maintain the conduction of triode Q5 for 1S of time. After the time delay, the oscillation phenomenon that the laser is turned off after protection, and then turned on and turned off immediately after the temperature is slightly lower than the threshold voltage will be effectively avoided.

[0033] Product test: use Type-C plug to power the module, turn on the slide switch to the "on" position, at which time the power indicator light is on, and the laser starts to output;

[0034] Use an optical power meter to measure the laser output power, and the actual measured value is 5-10mW of light source;

[0035] Laser constant current 0.18A, active refrigeration constant current 2A, maximum power consumption of the whole machine is about 2.2A;

[0036] Temperature protection part: when the laser temperature is greater than the threshold value of starting refrigeration, the TEC active refrigeration will be started, and when the TEC current is pulled to 2A, it will run stably. When active cooling cannot meet the laser cooling temperature rising to the temperature protection threshold, the laser output will be turned off. After the laser is turned off due to over-temperature, the laser will have a short delay, at which time it cannot be turned on to avoid excessive heat accumulation.

Claims

1. A micro seed light source module structure for a laser, comprising a housing (1), characterized in that: The outer casing (1) is equipped with a circuit board connected to the laser. The laser is connected to the fiber optic jumper (2). The outer casing (1) is equipped with a charging port (4). The circuit board includes a laser TEC constant current circuit, a PI temperature control circuit and an over-temperature protection circuit. The laser TEC constant current circuit includes an operational amplifier U1. The positive input terminal of the operational amplifier U1 is connected to a protection resistor R1. The output terminal of the operational amplifier U1 is connected to the base of the transistor Q1 through a resistor R7. The emitter of the transistor Q1 is connected to a resistor R8. The negative input terminal of the operational amplifier U1 is connected to a resistor R8 through a protection resistor R6. The negative input terminal and the output terminal of the operational amplifier U1 are connected to a filter capacitor C5.

2. The structure of the micro seed light source module for lasers according to claim 1, characterized in that: The charging port uses a Type-C interface; the fiber optic patch cord (2) is an FC / APC fiber optic pigtail patch cord.

3. The structure of the micro seed light source module for lasers according to claim 1, characterized in that: The PI temperature control circuit includes a Wheatstone bridge, which is connected to the positive input terminal of operational amplifier U2 through resistor R16 and to the negative input terminal of operational amplifier U2 through resistor R15. Resistor R20 and capacitor C13 are connected in series between the negative input terminal and the output terminal of operational amplifier U2.

4. The structure of the micro seed light source module for lasers according to claim 1, characterized in that: The over-temperature protection circuit includes an operational amplifier U3 and a transistor Q5. The positive input terminal of the operational amplifier U3 is connected to the protection circuit through a resistor R27, and the negative input terminal of the operational amplifier U3 is connected to the thermistor RT of the laser through a resistor R26. The base of the transistor Q5 is connected to a resistor R23 through a filter circuit, and the emitter of the transistor Q5 is connected to the B terminal of the common cathode diode D1.

5. The structure of the micro seed light source module for lasers according to claim 4, characterized in that: The protection circuit includes resistors R25 and R24 connected in series. The positive input terminal of operational amplifier U3 is connected between resistors R25 and R24 through resistor R27.

6. The structure of the micro seed light source module for lasers according to claim 4, characterized in that: The second filter circuit includes a resistor R28 and a capacitor C15. The resistor R28 and the capacitor C15 are connected in parallel and then connected between the base of the transistor Q5 and the resistor R23.

7. The structure of the miniature seed light source module for lasers according to claim 1, characterized in that: A filter circuit is also connected between the positive input terminal of the operational amplifier U1 and the protection resistor R1. The filter circuit includes a resistor R2 and a capacitor C3, which are connected in parallel between the positive input terminal of the operational amplifier U1 and the protection resistor R1.

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