Research On Weak Light Triggered Gallium Arsenide Photoconductive Switch Parallel Synthesis Technology

Compared with traditional switches,photoconductive semiconductor switches(GaAs PCSS)has the characteristics of small jitter,fast response,high frequency repetition,high voltage resistance and high conversion efficiency.GaAs PCSS has been widely used in pulse power technology,THz science and ultra-wideband microwave systems.Due to the cost and integration requirements in practical applications,laser diodes(LD)have attracted people’s attention as trigger light sources for GaAs PCSS.In particular,the discovery of the non-linear working mode in GaAs PCSS provides a theoretical basis for triggering GaAs PCSS output high-power electrical pulses on the order of μJ LD.In this paper,the characteristics of the output electric pulses in the linear operation mode of two parallel GaAs PCSS triggered by weak light are compared,and the factors affecting the voltage amplitude and synchronization of the two output electric pulses are analyzed.At the same time,the output electric pulses of the two-way switch in the linear mode and the non-linear mode are synthesized,which has a certain degree of guiding significance for the subsequent multi-way switch synthesis research.The thesis first compares the output electrical pulse characteristics of two parallel GaAs PCSS triggered by two laser diodes driven by independent modules.On this basis,the effects of the bias voltage applied across the switch and the operating voltage of the laser diode module on the characteristics of the two output electrical pulses are analyzed.The experimental results show that there is a difference in voltage amplitude and rising edge between the two electrical pulses.There is an unstable difference in the optical pulse characteristics when two laser diodes are driven independently,so the voltage amplitude and synchronization of the two output electrical pulses fluctuate.The increase in bias voltage is beneficial to the synchronization of the output.The synthesis of two different synthesis devices was carried out on the output pulses of two laser diodes independently triggering two parallel GaAs PCSS in linear mode.The evaluation criteria of the synthesis effect are given,and the factors affecting the synthesis effect are analyzed.The experimental results show that when the working voltage of the diode module is 190 V and the bias voltage at both ends of the switch is 200 V,the power divider synthesizes the two output electrical pulses to obtain an electrical pulse with a voltage amplitude increase of 1.4 times and a pulse width of 10 ns.The amplitude of the synthesized voltage can only be increased by 1.24 times,and the pulse width is expanded by 11 ns,the synthesis effect is not as good as the power divider.In further research,as the operating voltage of the laser diode module increases,the synthesis efficiency of the power divider gradually increases.As the delay of the driving signal of the laser diode module increases,the synthesis effect of the power divider becomes worse.The results of the composite analysis of the common divider show that the smaller the difference between the voltage amplitude and the rising edge of the two electrical pulses,the better the synthesis effect.The output electrical pulse characteristics of two parallel switches triggered by μJ-level laser pulses in non-linear working mode are compared.At the same time,the output pulses of the power divider,tee and copper wire were synthesized and studied.Experimental results show that the voltage amplitude and rising edge of the two electrical pulses are different.Because the characteristics of the output electric pulse in the non-linear mode are related to the carrier multiplication effect inside the switch,increasing the energy of the triggered optical pulse basically does not affect the size of the difference.In the synthesis of the three kinds of synthesis devices,the power splitter synthesis can obtain a voltage amplitude increase of 1.31 times when the switching light voltage is 30 μJ,the switching bias voltage is 5500 V,and the pulse width is only Ins.The synthesized electrical pulse is better than the tee and copper.The line has an unstable waveform and the pulse width expands to 11-14 ns.The research results have reference value for the synthesis of nonlinear output electrical pulses of parallel GaAs PCSS triggered by weak light.