Sub-nanosecond Rising-edge Narrow Pulse Driver Circuit and Analog Simulation
Semiconductor lasers have made great progress in theoretical research,practical application and technological development in the half century since their introduction.Today,they occupy the majority of the market share in the entire laser field,and are widely used in a variety of fields such as communication networks,medical aesthetics,laser sensing,and single-photon detection.Photon detection,for example,is a technique capable of detecting extremely low noise,with enhanced sensitivity enabling it to capture the smallest energy quantum of light,the photon.Not only does this technique allow for the precise counting of individual photons,which greatly enhances the accuracy and efficiency of detection,but it is also widely used in fields such as laser ranging and LIDAR to achieve high-resolution distance measurement and target detection.In laser ranging,the onset time of a laser pulse is usually defined by the rising edge of the pulse,so the steepness of the rising edge directly affects the accuracy of time-of-flight measurement.In LIDAR systems,a fast rising edge helps to shorten the laser emission time and increase the laser power,which in turn enhances the system's ability to sense the environment.Therefore,as the source of the laser signal,a semiconductor laser outputting narrow pulses with fast rising edges is crucial for improving the system accuracy.In this paper,a narrow pulse circuit with sub-nanosecond rising edge is designed,and the effects of inductance,capacitance and other parameters in the circuit on the rising edge of the output laser pulse are theoretically analyzed.The driver circuit uses a GaN integrated module with built-in driver as the main switch,and the semiconductor laser diode is driven by a reasonably designed driver circuit.At the same time,Field Programmable Gate Array(FPGA)is used as the control core to design the timing signals to realize the precise adjustment of the laser diode's pulse width and repetition frequency;and the thermoelectric cooler is driven by ADN8831 to realize the constant temperature control of the semiconductor laser.By simulating the circuit,it was found that the capacitor's ability to store and release energy increases with its value,allowing the circuit to release more charge per pulse,resulting in wider pulses and higher peak currents.Resistance only affects the peak current and an increase in resistance decreases the peak current.An increase in inductance extends the duration of the rising edge and reduces the peak current.Parasitic parameters in loop circuits,such as inductance,not only affect the speed of the pulse,but also affect the pulse waveform,making it more rounded or"dome"shaped.A relatively small capacitance has no significant effect on the overall performance.By reasonably designing the inductance and capacitance parameters and optimizing the circuit layout and wiring,sub-nanosecond rising edge laser narrow pulses can be achieved.The final experimental validation shows that the pulse front reaches 630 ps,the pulse width is adjustable from 5 ns to 15 ns,the repetition frequency is adjustable from 1 kHz to 10 kHz,the temperature of the LD is set from 25℃to 26℃,and the RMS test value of the 12-hour power stability is 0.51%.
Sub-nanosecond rising edgeNarrow pulse widthFPGADriver circuitsTemperature control
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维普
