Pulse width adaptive delay modulation circuit suitable for erbium glass laser

Abstract

The utility model discloses a pulse width adaptive delay modulation circuit suitable for an erbium glass laser, which comprises an erbium glass laser, an input signal shaping circuit, an optical signal detection shaping circuit, a delay trigger circuit and a logic control output circuit, the input signal shaping circuit receives and shapes an external input signal and then outputs a driving signal to the logic control output circuit; the optical signal detection shaping circuit collects an optical signal, shapes the optical signal into a digital signal and transmits the digital signal to the delay trigger circuit, and the delay trigger circuit delays the received signal and transmits the signal to the logic control circuit; and the logic control circuit performs logic operation on the received two paths of signals and outputs a final driving signal to the erbium glass laser to form closed-loop control. According to the utility model, the light emitting condition of the erbium glass laser can be simply and effectively identified, a signal output by the input signal shaping circuit and a signal shaped during light emitting of the erbium glass laser are logically processed and then a driving signal is output, self-adaptive judgment control is realized, complex operation is not needed, the applicability of the driving circuit is improved, and the cost is reduced. And the driving application of the erbium glass laser is greatly simplified.

Description

Technical Field

[0001] The utility model relates to the technical field of laser optoelectronics, and particularly relates to a pulse width adaptive delay modulation circuit applicable to an erbium glass laser. Background Art

[0002] Laser technology is widely used in the field of laser ranging. The laser wavelength band of an erbium glass laser is about 1535nm. The beam energy is concentrated and eye-safe, and it can achieve accurate long-distance target measurement, which is very suitable for medium and long-distance laser ranging systems.

[0003] In the prior art, the erbium glass laser adopts a passive Q-switching method, and the constant current drive pulse width is affected by the rise / fall time of the pump source, the doping characteristics of erbium ions in the working substance, and the thermal loss during assembly and adjustment. The existing technology cannot ensure complete consistency from materials to final assembly. Therefore, the laser pulse widths of erbium glass are not consistent. In addition, during use, due to problems such as long-term thermal effect accumulation, aging of optical elements, reduction of pump source power, and absorption efficiency in high and low temperature environments, the drive pulse width will also change to a certain extent and is not deterministic. When the drive pulse width is not accurately controlled, if the drive pulse width is less than the critical rated pulse width for light output, the laser will not emit light and cannot work; if the drive pulse width is greater than the critical rated pulse width for light output, the laser may emit light multiple times. In addition, the light-light conversion efficiency is reduced, the thermal loss is increased, and the service life of the product is greatly reduced.

[0004] In the above working principle, the electrical pulse width drive of the erbium glass laser is not consistent and deterministic, but precise control is required during use and application. At the same time, when high-reliability products are applied, it is necessary to test the electrical pulse width characteristics of the laser in different environments. The test assembly steps are numerous, the process is complex, the cost is high, and the cycle is long. Therefore, how to simply and reliably adjust the electrical pulse width of the drive erbium glass laser is an urgent problem to be solved. Summary of the Utility Model

[0005] In view of this, to solve the above deficiencies of the prior art, the purpose of the present utility model is to provide a pulse width adaptive delay modulation circuit applicable to an erbium glass laser, which can simply and effectively identify the light output situation of the erbium glass laser, make an adaptive delay to accurately adjust the electrical pulse width of the laser, and overcome the problems of poor consistency, determinacy, and adaptability of the electrical drive pulse width when driving an erbium glass laser in the existing laser ranging technology.

[0006] To achieve the above purpose, the technical solution adopted by the present utility model is as follows:

[0007] A pulse-width adaptive delay modulation circuit applicable to an erbium glass laser, comprising an erbium glass laser, an input signal shaping circuit, an optical signal detection and shaping circuit, a delay trigger circuit, and a logic control output circuit;

[0008] The input signal shaping circuit is configured to receive an external input signal, and after shaping, output a driving signal to the logic control output circuit;

[0009] The optical signal detection and shaping circuit is configured to collect the optical signal of the erbium glass laser and shape it into a digital signal for transmission to the delay trigger circuit as the basis for feedback modulation;

[0010] The delay trigger circuit is configured to perform a microsecond-level delay processing on the digital signal of the previous stage and transmit a delay trigger signal to the logic control circuit;

[0011] The logic control circuit is configured to receive the signal of the input signal shaping circuit and transmit the driving signal to the erbium glass laser; it is also configured to receive the signal of the delay trigger circuit, perform digital logic operations on the received delay trigger signal and driving signal, and output a final driving signal to the erbium glass laser.

[0012] Further, the pulse width of the delay trigger signal is greater than the pulse width of the driving signal.

[0013] Further, the input signal shaping circuit includes a Schmitt trigger, and the external input signal is shaped by the Schmitt trigger into a maximum pulse width driving signal that is compatible with the driving conditions of the erbium glass laser and has a redundancy.

[0014] Still further, the external input signal is transmitted to pin 2 of the Schmitt trigger of the input signal shaping circuit to trigger the rising edge of the input signal.

[0015] Still further, the external input signal is transmitted to pin 1 of the Schmitt trigger of the input signal shaping circuit to trigger the falling edge of the input signal.

[0016] Further, the optical signal detection and shaping circuit uses a photodiode connected in reverse, receives the optical signal of the erbium glass laser to generate a current, and converts it into an analog voltage signal through a pull-down resistor for transmission to the delay trigger circuit, and is shaped into a digital signal with a specific pulse width by the delay trigger circuit.

[0017] Still further, the pulse width of the digital signal output by the delay trigger circuit is the delay time after the light output.

[0018] The beneficial effects of the present utility model:

[0019] The utility model only collects the light output of the laser, uses a general Schmitt trigger and logic gates to complete the adaptive closed-loop control, without complex algorithms and is more stable and reliable. It can simply and effectively identify the light output of the erbium glass laser, make an adaptive delay, and accurately adjust the electrical pulse width of the laser, overcoming the problems of poor consistency, determinacy, and adaptability of the electrical drive pulse width when driving the erbium glass laser in the existing laser ranging technology;

[0020] The signal output by the input signal shaping circuit and the signal shaped when the erbium glass laser emits light are logically processed to output a drive signal, and the adaptive judgment control is carried out. Without complex operations, only three devices, namely a Schmitt trigger, a NOT gate, and a NOT gate, are required to complete the signal closed-loop modulation. It can solve the problems of non-light output, multiple light emissions, and reduced lifespan when driving the erbium glass laser, improve the applicability of the drive circuit, and greatly simplify the drive application of the erbium glass laser. Brief Description of the Drawings

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0022] Figure 1 It is the schematic diagram of the pulse width adaptive delay modulation circuit of the present utility model;

[0023] Figure 2 It is the signal control logic diagram of the pulse width adaptive delay modulation circuit in Embodiment 2;

[0024] Figure 3 It is the schematic diagram of the input signal shaping circuit in Embodiment 2;

[0025] Figure 4 It is the schematic diagram of the optical signal detection and shaping circuit in Embodiment 2;

[0026] Figure 5 It is the schematic diagram of the delay trigger circuit in Embodiment 2;

[0027] Figure 6 It is the schematic diagram of the logic control circuit in Embodiment 2. Detailed Embodiments

[0028] The following gives specific embodiments to further clearly, completely, and detailedly illustrate the technical solutions of the present utility model. This embodiment is the best embodiment based on the technical solutions of the present utility model, but the protection scope of the present utility model is not limited to the following embodiments.

[0029] Embodiment 1

[0030] A pulse-width adaptive delay modulation circuit applicable to an erbium glass laser, comprising an erbium glass laser, an input signal shaping circuit, an optical signal detection and shaping circuit, a delay trigger circuit, and a logic control output circuit;

[0031] The input signal shaping circuit is used to receive an external input signal, shape it and output a driving signal to the logic control output circuit, and the pulse-width parameter of this circuit is adjusted according to the driving conditions of the erbium glass laser;

[0032] The optical signal detection and shaping circuit is used to collect the optical signal of the erbium glass laser, shape it into a digital signal and transmit it to the delay trigger circuit as the basis for feedback modulation;

[0033] The delay trigger circuit is used to perform a microsecond-level delay processing on the digital signal of the previous stage and transmit a delay trigger signal to the logic control circuit;

[0034] The logic control circuit is used to receive the signal of the input signal shaping circuit, transmit the driving signal to the erbium glass laser; it is also used to receive the signal of the delay trigger circuit, perform digital logic operations on the received delay trigger signal and driving signal, and output a final driving signal to the erbium glass laser.

[0035] The signal sequentially passes through the input signal shaping circuit, the logic control output circuit to the erbium glass laser to generate an optical signal, and then the optical signal is shaped into a digital signal by the optical signal detection and shaping circuit and reaches the logic control output circuit through the delay trigger circuit. The logic control output circuit performs digital logic operations on the output signal of the input signal shaping circuit and the output signal of the delay trigger circuit and then outputs the final driving signal to the erbium glass laser to form a closed-loop control. It can simply and effectively identify the light output situation of the erbium glass laser, make an adaptive delay, and precisely control the electrical pulse width of the laser.

[0036] Further, the pulse width of the delay trigger signal is greater than the pulse width of the driving signal.

[0037] Further, the input signal shaping circuit includes a Schmidt trigger, and the external input signal is shaped into a maximum pulse-width driving signal that is compatible with the driving conditions of the erbium glass laser and has a redundant amount by the Schmidt trigger. This circuit only completes the adaptive closed-loop control by collecting the light output situation of the laser, using a general Schmidt trigger and logic gates, without complex algorithms and is more stable and reliable.

[0038] Furthermore, the external input signal is transmitted to pin 2 or pin 1 of the Schmidt trigger of the input signal shaping circuit to trigger the input signal on the rising edge or falling edge.

[0039] Further, the optical signal detection and shaping circuit uses a photodiode connected in reverse. It receives the optical signal of the erbium-doped glass laser to generate a current, which is converted into an analog voltage signal through a pull-down resistor and sent to the delay trigger circuit. The delay trigger circuit shapes it into a digital signal with a specific pulse width. The pulse width of the digital signal output by the delay trigger circuit is the delay time after the light output.

[0040] Further, the optical signal detection and shaping circuit judges the light output situation of the erbium-doped glass laser through photoelectric conversion to form a feedback adjustment driving signal.

[0041] Embodiment 2

[0042] A pulse width adaptive delay modulation circuit applicable to an erbium-doped glass laser disclosed by the present utility model generates a signal triggered by a controller or an external mechanical switch. This signal follows the light output of the control signal. The signal edge is shaped into a maximum pulse width driving signal that is compatible with various driving conditions of the erbium-doped glass laser and has a sufficient redundancy by a Schmitt trigger. This driving signal controls a constant current circuit to inject current into the laser pump source. After the laser emits light, the optical sampling circuit collects optical information and shapes and converts it into an electrical signal, performs a us-level delay trigger to ensure the stability of the laser light output, and then modulates and outputs the final laser driving signal through a logic control circuit.

[0043] In this embodiment, the pulse width parameter of the input signal shaping circuit is 4 ms. The delay trigger circuit needs to output a signal with a larger pulse width that is at least greater than the 4 ms of the input shaping. As an option, it can be set to 10 ms.

[0044] Specifically, the driving pulse width of the erbium-doped glass laser is generally between 1 ms and 2 ms. The input signal shaping circuit outputs a signal with a 4-ms pulse width to leave a 50% design margin; the output signal of the optical signal detection and shaping can be set to 5 us for delay to ensure the stability of the optical signal during the light output process of the erbium-doped glass laser.

[0045] The working principle is as follows:

[0046] The controller inputs a laser start signal Sig_in. This signal does not need to be precisely restricted in terms of the rising / falling rate, width, etc. The Schmitt trigger in the input signal shaping circuit shapes this signal into a stable and reliable digital signal Tri_smt; the erbium-doped glass laser emits light, and the optical signal detection and shaping circuit receives the optical signal and shapes it into a digital signal Start. The signal Start is subjected to a us-level delay trigger by the delay trigger circuit to output a signal Delay; after the logical processing of the signal Tri_smt and the signal Delay, a driving signal Tri_out is output and sent to the erbium-doped glass laser for adaptive judgment and control. Without complex calculations, only three devices, namely a Schmitt trigger, a NOT gate, and a NOT gate, are required to complete the signal closed-loop modulation.

[0047] In summary, a pulse width adaptive delay modulation circuit for an erbium glass laser of the present utility model can simply and effectively identify the light output situation of the erbium glass laser, and make an adaptive delay, greatly improving the production efficiency, reducing the production cost, and improving the applicability of the erbium glass laser in a complex environment.

[0048] The foregoing has shown and described the main features, basic principles and advantages of the present utility model. Those skilled in the art should understand that the present utility model is not limited by the above-mentioned embodiments, and what is described in the above-mentioned embodiments and the specification is only to illustrate the principle of the present utility model. Without departing from the spirit and scope of the present utility model, the present utility model will also have various changes and improvements according to actual situations, and these changes and improvements all fall within the scope of the present utility model claimed. The scope of protection claimed by the present utility model is defined by the appended claims and their equivalents.

Claims

1. A pulse width adaptive delay modulation circuit applicable to an erbium glass laser, characterized in that It includes an erbium-doped glass laser, an input signal shaping circuit, an optical signal detection and shaping circuit, a delay trigger circuit, and a logic control output circuit; The input signal shaping circuit is used to receive an external input signal, and after shaping, output a driving signal to the logic control output circuit; The optical signal detection and shaping circuit is used to collect the optical signal of the erbium-doped glass laser and shape it into a digital signal for transmission to the delay trigger circuit; The delay trigger circuit is used to perform a microsecond-level delay processing on the digital signal of the previous stage and transmit a delay trigger signal to the logic control circuit; The logic control circuit is used to receive the signal of the input signal shaping circuit and transmit the driving signal to the erbium-doped glass laser; it is also used to receive the signal of the delay trigger circuit, perform digital logic operations on the received delay trigger signal and driving signal, and output a final driving signal to the erbium-doped glass laser.

2. The pulse width adaptive delay modulation circuit applicable to an erbium glass laser according to claim 1, wherein The pulse width of the delay trigger signal is greater than the pulse width of the driving signal.

3. The pulse-width adaptive delay modulation circuit applicable to an erbium glass laser according to claim 1, wherein The input signal shaping circuit includes a Schmitt trigger, and the external input signal is shaped by the Schmitt trigger into a maximum pulse width driving signal that is compatible with the driving conditions of the erbium-doped glass laser and has a redundant amount.

4. The pulse width adaptive delay modulation circuit applicable to an erbium glass laser according to claim 3, characterized in that, The external input signal is transmitted to pin 2 of the Schmitt trigger of the input signal shaping circuit to trigger the rising edge of the input signal.

5. The pulse-width adaptive delay modulation circuit for an erbium glass laser according to claim 3, characterized in that The external input signal is transmitted to pin 1 of the Schmitt trigger of the input signal shaping circuit to trigger the falling edge of the input signal.

6. The pulse-width adaptive delay modulation circuit applicable to an erbium glass laser according to claim 1, wherein The optical signal detection and shaping circuit uses a photodiode connected in reverse, receives the optical signal of the erbium-doped glass laser to generate a current, and converts it into an analog voltage signal through a pull-down resistor for transmission to the delay trigger circuit, and is shaped into a digital signal with a specific pulse width by the delay trigger circuit.

7. The pulse width adaptive delay modulation circuit for an erbium glass laser according to claim 6, characterized in that, The pulse width of the digital signal output by the delay trigger circuit is the delay time after the light output.

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