Pulsed semiconductor laser

Abstract

The application provides a kind of pulse semiconductor laser.The pulse semiconductor laser includes pulse width adjusting circuit and drive circuit;Drive circuit includes laser chip;Pulse width adjusting circuit is used to pulse width adjustment to input pulse electric signal, obtains output pulse electric signal;The pulse width of output pulse electric signal is positively correlated with ambient temperature;Drive circuit is used to drive laser chip to emit laser according to output pulse electric signal, and make the current flowing through laser chip positively correlated with ambient temperature;The optical pulse width of laser chip is positively correlated with the pulse width of output pulse electric signal.The application can keep the single pulse energy of laser output stable when ambient temperature changes.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor laser, and particularly to a pulsed semiconductor laser. BACKGROUND

[0002] The pulsed semiconductor laser has been widely applied to the fields of ranging, detection, laser fuse, laser guidance, laser radar and the like due to its small volume, low power consumption and high reliability. With the development of technology, higher requirements are put forward for the output single pulse energy stability of the laser light source.

[0003] At present, the output single pulse energy of the laser varies greatly with temperature, resulting in poor output single pulse energy stability of the laser. SUMMARY

[0004] The embodiment of the present application provides a pulsed semiconductor laser to solve the problem of poor output single pulse energy stability of the laser.

[0005] The embodiment of the present application provides a pulsed semiconductor laser, comprising a pulse width adjusting circuit and a driving circuit; the driving circuit comprises a laser chip;

[0006] The pulse width adjusting circuit is used for pulse width adjusting of an input pulse electrical signal to obtain an output pulse electrical signal; the pulse width of the output pulse electrical signal is positively correlated with the ambient temperature;

[0007] The driving circuit is used for driving the laser chip to emit laser light according to the output pulse electrical signal, and making the current flowing through the laser chip positively correlated with the ambient temperature; the light pulse width of the laser chip is positively correlated with the pulse width of the output pulse electrical signal.

[0008] In a possible implementation manner, the pulse width adjusting circuit comprises a D flip-flop, a first power tube, a first capacitor, a second capacitor and a first resistor; the capacitance of the second capacitor is positively correlated with the ambient temperature;

[0009] The D flip-flop is used for receiving the input pulse electrical signal at the first input end, connecting the first power supply at the second input end, connecting the first output end with the first end of the first resistor and the first end of the first power tube, outputting the output pulse electrical signal at the second output end, and connecting the second output end with the control end of the first power tube and the first end of the second capacitor;

[0010] The first capacitor is used for connecting the second power supply at the first end, connecting the second end with the second end of the first resistor, and grounding the second end;

[0011] The second end of the first power tube and the second end of the second capacitor are both used for grounding.

[0012] In a possible implementation, the pulse width modulation circuit further includes a second resistor;

[0013] The second output terminal of the D trigger is connected to the control terminal of the first power tube and the first terminal of the second capacitor through the second resistor.

[0014] In a possible implementation, the pulse width modulation circuit further includes a third resistor;

[0015] The third resistor has a first end connected to the first input end of the D flip-flop and a second end grounded.

[0016] In a possible implementation, in the D flip-flop, the power terminal is used to be connected to the second power supply, and the ground terminal is used to be grounded.

[0017] In a possible implementation, the second capacitor is a ceramic capacitor.

[0018] In a possible implementation, both the first power supply and the second power supply output a +5V voltage.

[0019] In a possible implementation, the driving circuit further includes a second power tube, a third capacitor, and a fourth resistor; the fourth resistor is a negative temperature coefficient resistor;

[0020] A second power tube, the control end of which is used to receive the output pulse electrical signal, the first end of which is connected to the first end of the laser chip, and the second end of which is grounded via a fourth resistor;

[0021] The second end of the laser chip is connected to the first end of the third capacitor, and the second end of the laser chip is also used to connect to the third power supply;

[0022] The second terminal of the third capacitor is grounded.

[0023] In a possible implementation, the driving circuit further includes a fifth resistor;

[0024] The first end of the second power tube is connected to the first end of the laser chip through a fifth resistor.

[0025] In a possible implementation, the driving circuit further includes a sixth resistor;

[0026] The second end of the laser chip is connected to the third power supply through a sixth resistor.

[0027] The embodiment of the present application provides a pulse semiconductor laser, the pulse width of an input pulse electric signal can be adjusted through a pulse width adjusting circuit, so that the output pulse electric signal is positively correlated with the ambient temperature, the current flowing through the laser chip is positively correlated with the ambient temperature through a driving circuit, and the laser chip is driven to emit laser through the output pulse electric signal, so that the light pulse width of the laser chip is positively correlated with the pulse width of the output pulse electric signal, thereby the single pulse energy of the laser output can be kept stable when the ambient temperature changes. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0029] Figure 1 Fig. 1 is a structural schematic diagram of a pulse semiconductor laser provided by the embodiment of the present application;

[0030] Figure 2 Fig. 2 is a circuit schematic diagram of a pulse width adjusting circuit provided by the embodiment of the present application;

[0031] Figure 3 Fig. 3 is a circuit schematic diagram of a driving circuit provided by the embodiment of the present application;

[0032] Figure 4 Fig. 4 is a whole structural schematic diagram of a pulse semiconductor laser provided by the embodiment of the present application. DETAILED DESCRIPTION

[0033] In order to make the personnel in the technical field better understand the present application, the technical solutions in the embodiments of the present application will be clearly described in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should belong to the protection scope of the present application.

[0034] The terms "include", and other any variants thereof, in the specification and claims of the present application and the above drawings, refer to "include but not limited to", and are intended to cover the non-exclusive inclusion, and are not limited to the examples listed in the text. In addition, the terms "first" and "second" and the like are used to distinguish different objects, not to describe a specific order.

[0035] The implementation of the present application will be described in detail in combination with specific drawings:

[0036] Figure 1 A structure schematic diagram of a pulse semiconductor laser is provided for an embodiment of the present application. Referring to Figure 1 , the pulse semiconductor laser comprises a pulse width adjusting circuit 11 and a driving circuit 12; the driving circuit 12 comprises a laser chip LD;

[0037] The pulse width adjusting circuit 11 is used for pulse width adjusting of an input pulse electric signal TTLIN to obtain an output pulse electric signal TTLOUT; the pulse width of the output pulse electric signal TTLOUT is positively correlated with the ambient temperature;

[0038] The driving circuit 12 is used for driving the laser chip LD to emit laser according to the output pulse electric signal TTLOUT, and making the current flowing through the laser chip LD positively correlated with the ambient temperature; the light pulse width of the laser chip LD is positively correlated with the pulse width of the output pulse electric signal TTLOUT.

[0039] Wherein, the laser output single pulse energy E=(the current I flowing through the laser chip LD×the slope efficiency η) / the light pulse width T W .

[0040] The current flowing through the laser chip LD can also be called the driving current or pulse driving current of the laser chip LD.

[0041] The slope efficiency η of the laser chip LD decreases with the increase of the ambient temperature, that is, the slope efficiency η of the laser chip LD is negatively correlated with the ambient temperature.

[0042] In order to ensure the stability of the laser output single pulse energy, the pulse width adjusting circuit 11 is used for pulse width adjusting of the input pulse electric signal TTLIN to obtain the output pulse electric signal TTLOUT in the embodiment, the pulse width of the output pulse electric signal TTLOUT is positively correlated with the ambient temperature, and the light pulse width T W of the laser chip LD is positively correlated with the pulse width of the output pulse electric signal TTLOUT, so the light pulse width T W of the laser chip LD is positively correlated with the ambient temperature.

[0043] The driving circuit 12 is used for making the current I flowing through the laser chip LD positively correlated with the ambient temperature in the embodiment.

[0044] In the embodiment, when the ambient temperature increases, the slope efficiency η decreases, and the current I flowing through the laser chip LD and the light pulse width T WIncrease to offset the effect of the decrease in slope efficiency η; when the ambient temperature decreases, the slope efficiency η increases, by making the current I flowing through the laser chip LD and the optical pulse width T W It is reduced to offset the effect of the increase in slope efficiency η, thereby stabilizing the single pulse energy output by the laser.

[0045] Among them, the specific positive correlation between the pulse width of the output pulse electrical signal TTLOUT and the ambient temperature, the specific positive correlation between the current flowing through the laser chip LD and the ambient temperature, and the specific positive correlation between the light pulse width of the laser chip LD and the pulse width of the output pulse electrical signal TTLOUT can be determined through relevant experiments and are not specifically limited here.

[0046] In this embodiment, the pulse width adjustment circuit 11 can adjust the pulse width of the input pulse electrical signal TTLIN, so that the output pulse electrical signal TTLOUT is positively correlated with the ambient temperature. The driving circuit 12 can make the current flowing through the laser chip LD positively correlated with the ambient temperature, and the laser chip LD is driven to emit laser by the output pulse electrical signal TTLOUT, so that the optical pulse width of the laser chip LD is positively correlated with the pulse width of the output pulse electrical signal TTLOUT, so that the single pulse energy output by the laser can remain stable when the ambient temperature changes.

[0047] In some embodiments, see Figure 2 The pulse width modulation circuit 11 includes a D trigger U1, a first power tube Q1, a first capacitor C1, a second capacitor C2 and a first resistor R2; the capacitance of the second capacitor C2 is positively correlated with the ambient temperature;

[0048] A D flip-flop U1, having a first input terminal for receiving an input pulse electrical signal TTLIN, a second input terminal for connecting to a first power supply, a first output terminal connected to a first terminal of a first resistor R2 and a first terminal of a first power transistor Q1, a second output terminal for outputting an output pulse electrical signal TTLOUT, and a second output terminal further connected to a control terminal of the first power transistor Q1 and a first terminal of a second capacitor C2;

[0049] A first capacitor C1, having a first end connected to the second power supply, the first end also connected to the second end of the first resistor R2, and a second end connected to the ground GND;

[0050] The second end of the first power tube Q1 and the second end of the second capacitor C2 are both connected to the ground GND.

[0051] See also Figure 2 The first input of the D flip-flop U1 is the 1st pin (CP) of U1, the second input of the D flip-flop U1 is the 3rd pin (D) of U1, and the first output of the D flip-flop U1 is the 6th pin of U1. The second output terminal of the D flip-flop U1 is pin 4 (Q) of U1.

[0052] The control terminal of the first power transistor Q1 is pin 1 (G) of Q1, the first terminal of the first power transistor Q1 is pin 3 (D) of Q1, and the second terminal of the first power transistor Q1 is pin 2 (S) of Q1. The first power transistor Q1 can be a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor).

[0053] When the D-type flip-flop U1 captures the rising edge of the input pulse electrical signal TTLIN, the second output terminal of the D-type flip-flop U1 outputs a high level. The high level output by the second output terminal of the D-type flip-flop U1 charges the second capacitor C2 and the capacitance of the control end of the first power tube Q1 (i.e., the gate capacitance). After charging is completed, the first output terminal of the D-type flip-flop U1, i.e., pin 6, is at a low level, and the second output terminal of the D-type flip-flop U1 is at a low level, thereby realizing the pulse width conversion function.

[0054] When the ambient temperature rises, the capacitance of the second capacitor C2 increases, and the pulse width of the output pulse electrical signal TTLOUT also increases; when the ambient temperature decreases, the capacitance of the second capacitor C2 decreases, and the pulse width of the output pulse electrical signal TTLOUT also decreases.

[0055] The pulse width modulation circuit 11 provided in this embodiment is an adaptive adjustable pulse width circuit, which is implemented by using a D flip-flop U1, a first power tube Q1, a second capacitor C2, and peripheral resistors and capacitors to convert different pulse electrical signals input from the outside into pulse outputs that are dynamically adjusted with temperature.

[0056] In some embodiments, see Figure 2 , the pulse width modulation circuit 11 further includes a second resistor R3;

[0057] The second output terminal of the D flip-flop U1 is connected to the control terminal of the first power tube Q1 and the first terminal of the second capacitor C2 through the second resistor R3.

[0058] In some embodiments, see Figure 2 , the pulse width modulation circuit 11 further includes a third resistor R1;

[0059] The third resistor R1 has a first end connected to the first input end of the D flip-flop U1 , and a second end connected to the ground GND.

[0060] In some embodiments, see Figure 2 , the D flip-flop U1, the power supply terminal is used to be connected to the second power supply, and the ground terminal is used to be grounded GND.

[0061] See also Figure 2 , the power supply terminal of the D flip-flop U1 is pin 5 (VCC) of U1, and the ground terminal of the D flip-flop U1 is pin 2 (GND) of U1.

[0062] In some embodiments, the second capacitor C2 is a ceramic capacitor.

[0063] In some embodiments, both the first power supply and the second power supply output a +5V voltage.

[0064] It should be noted that the first power supply and the second power supply can be the same power supply or different power supplies, and both output a +5V voltage.

[0065] In some embodiments, see Figure 3 The driving circuit 12 further includes a second power tube Q2, a third capacitor C3 and a fourth resistor R6; the fourth resistor R6 is a negative temperature coefficient resistor;

[0066] The second power tube Q2 has a control end for receiving the output pulse electrical signal TTLOUT, a first end connected to the first end of the laser chip LD, and a second end connected to the ground GND via a fourth resistor R6;

[0067] The second end of the laser chip LD is connected to the first end of the third capacitor C3, and the second end of the laser chip LD is also used to be connected to the third power supply VCC1;

[0068] A second terminal of the third capacitor C3 is connected to the ground GND.

[0069] The third power supply VCC1 is an external power supply, and the third capacitor C3 is an energy storage capacitor. The second power transistor Q2 can be a MOS transistor. The fourth resistor R6 is a negative temperature coefficient resistor, which can be implemented using thick film or thin film processes. The number of laser chips LD can be set according to actual needs and is not specifically limited here. During the assembly process, the laser chip LD assembly and circuit assembly must have a temperature gradient. Figure 4 1 is a schematic diagram of the overall structure of a pulsed semiconductor laser provided by an embodiment of the present invention, which shows the assembly positions of some components of the laser.

[0070] When the output pulse signal TTLOUT is low, the second power transistor Q2 is turned off, and the third power supply VCC1 charges the third capacitor C3, which then stores energy. When the output pulse signal TTLOUT is high, the second power transistor Q2 is turned on, and the energy stored in the third capacitor C3 is released through the laser chip LD, the second power transistor Q2, and the fourth resistor R6, generating a pulsed drive current that drives the laser chip LD to emit light. The laser light pulse width is determined by the pulse width of the output pulse signal TTLOUT, and they are positively correlated.

[0071] According to the above description, the laser output single pulse energy E = (current I flowing through the laser chip LD × slope efficiency η) / optical pulse width T W When the ambient temperature rises, the resistance of the fourth resistor R6 decreases, the overall resistance of the circuit of the driving circuit 12 decreases, the pulse driving current I increases, the capacitance of the second capacitor C2 increases, the pulse width of the output pulse electrical signal TTLOUT increases, and the optical pulse width T W When the ambient temperature decreases, the resistance of the fourth resistor R6 increases, the overall resistance of the circuit of the driving circuit 12 increases, the pulse driving current I decreases, the capacitance of the second capacitor C2 decreases, the pulse width of the output pulse electrical signal TTLOUT decreases, and the optical pulse width T W Become smaller.

[0072] Since the slope efficiency η of the laser chip LD decreases with increasing temperature and increases with decreasing temperature, when the temperature rises, the drive current I and the output pulse width T are increased. W To achieve the stable output of laser single pulse energy E, when the temperature drops, the drive current I and output pulse width T are reduced. W To achieve stable output of laser single pulse energy E.

[0073] In some embodiments, the driving circuit 12 further includes a fifth resistor R5;

[0074] The first end of the second power tube Q2 is connected to the first end of the laser chip LD through the fifth resistor R5.

[0075] The fifth resistor R5 is a loop resistor.

[0076] In this embodiment, the third capacitor C3 can be implemented by a chip capacitor, and its specific parameters need to match the optoelectronic parameters and loop resistance parameters of the laser chip LD to ensure stable laser power output in a wide temperature range.

[0077] In some embodiments, the driving circuit 12 further includes a sixth resistor R4;

[0078] The second end of the laser chip LD is connected to the third power supply VCC1 through the sixth resistor R4.

[0079] The sixth resistor R4 is a current limiting resistor.

[0080] When the output pulse electrical signal TTLOUT is at a low level, the second power tube Q2 is turned off, and the third power supply VCC1 charges the third capacitor C3 through the sixth resistor R4, and the third capacitor C3 stores energy. When the output pulse electrical signal TTLOUT is at a high level, the second power tube Q2 is turned on, and the energy stored in the third capacitor C3 is released through the laser chip LD, the fifth resistor R5, the second power tube Q2, and the fourth resistor R6, generating a pulse drive current that drives the laser chip LD to emit light.

[0081] The driving circuit 12 is implemented using a general energy compression principle. In terms of the energy discharge circuit, a negative temperature coefficient material resistor is used in series in the circuit as part of the discharge loop. The resistance of the material decreases as the temperature increases, so that the driving current increases as the temperature increases. Since the electro-optical conversion efficiency of the laser chip LD decreases as the temperature increases, the output power is increased by increasing the driving current to achieve stable laser power output.

[0082] In a possible implementation, the capacitor in the pulsed semiconductor laser can be implemented using a silicon-based integrated capacitor.

[0083] This embodiment of the present invention relates to an integrated packaging design for an adaptively adjustable pulse width modulation circuit 11, a pulsed laser chip LD, and an adaptive dynamically adjustable drive circuit 12. This circuit dynamically adjusts the output of the drive current as it changes with temperature, and dynamically adjusts the optical pulse width. When integrated with the laser chip LD, this circuit achieves stable single-pulse energy output.

[0084] To achieve stable single-pulse energy output over a wide temperature range, the laser chip LD has different electro-optical conversion efficiencies at different temperatures, resulting in different laser output powers. Therefore, it is necessary to dynamically adjust the laser drive current at different temperatures. Under constant input signal pulse conditions, the optical pulse widths caused by the driver circuit 12 vary slightly at different temperatures, so dynamic adjustment of the optical pulse widths at different temperatures is necessary.

[0085] In this embodiment, adjusting the optical pulse width or the drive current alone cannot achieve the goal of stable laser single pulse energy output. By dynamically adjusting both, stable laser single pulse energy output is achieved. It should be noted that the parameters of the various components in the pulse width modulation circuit 11 and the drive circuit 12 can be determined through experiments and are not specifically limited here.

[0086] The embodiment of the present invention integrates the laser chip LD with the pulse width modulation circuit 11 and the driving circuit 12 in a package, adopts the pulse width modulation circuit 11 to adaptively and dynamically adjust the laser driving pulse width, and adaptively and dynamically adjusts the regulation current of the laser chip LD through the driving circuit 12, thereby ultimately achieving stable output of laser single pulse energy in a wide temperature range (-55°C to 125°C).

[0087] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A pulsed semiconductor laser, characterized in that: It includes a pulse width modulation circuit and a driving circuit; the driving circuit includes a laser chip; The pulse width modulation circuit is used to perform pulse width modulation on the input pulse electrical signal to obtain an output pulse electrical signal; The pulse width of the output pulse electrical signal is positively correlated with the ambient temperature; The driving circuit is used to drive the laser chip to emit laser light according to the output pulse electrical signal, and make the current flowing through the laser chip positively correlated with the ambient temperature; the optical pulse width of the laser chip is positively correlated with the pulse width of the output pulse electrical signal; The pulse width modulation circuit includes a D trigger, a first power tube, a first capacitor, a second capacitor and a first resistor; the capacitance of the second capacitor is positively correlated with the ambient temperature; The D flip-flop has a first input end for receiving the input pulse electrical signal, a second input end for connecting to a first power supply, a first output end connected to the first end of the first resistor and the first end of the first power tube, a second output end for outputting the output pulse electrical signal, and the second output end is further connected to the control end of the first power tube and the first end of the second capacitor, respectively; The first capacitor has a first end connected to the second power supply, the first end is also connected to the second end of the first resistor, and the second end is grounded; The second end of the first power tube and the second end of the second capacitor are both grounded.

2. The pulsed semiconductor laser according to claim 1, wherein The pulse width modulation circuit further includes a second resistor; The second output end of the D trigger is connected to the control end of the first power tube and the first end of the second capacitor respectively through the second resistor.

3. The pulsed semiconductor laser according to claim 1, wherein The pulse width modulation circuit further includes a third resistor; The third resistor has a first end connected to the first input end of the D trigger, and a second end connected to the ground.

4. The pulsed semiconductor laser according to claim 1, wherein The D flip-flop has a power supply terminal for connecting to the second power supply, and a ground terminal for grounding.

5. The pulsed semiconductor laser according to claim 1, wherein The second capacitor is a ceramic capacitor.

6. The pulsed semiconductor laser according to claim 1, wherein The first power supply and the second power supply both output a +5V voltage.

7. The pulsed semiconductor laser according to claim 1, wherein The driving circuit further includes a second power tube, a third capacitor and a fourth resistor; the fourth resistor is a negative temperature coefficient resistor; The second power tube has a control end for receiving the output pulse electrical signal, a first end connected to the first end of the laser chip, and a second end connected to ground via the fourth resistor; The second end of the laser chip is connected to the first end of the third capacitor, and the second end of the laser chip is also used to connect to a third power supply; The second end of the third capacitor is grounded.

8. The pulsed semiconductor laser according to claim 7, wherein The driving circuit further includes a fifth resistor; The first end of the second power tube is connected to the first end of the laser chip through the fifth resistor.

9. The pulsed semiconductor laser according to claim 7, wherein The driving circuit further includes a sixth resistor; The second end of the laser chip is connected to the third power supply through the sixth resistor.

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