红外探测器的性能受内部结构各层掺杂浓度的影响，而倍增层掺杂浓度会明显改变器件的性能。为了降低暗电流，提高器件性能，采用三元化合物In_0.83Al_0.17As作为倍增层材料，借助仿真软件Silvaco详细研究了In_0.83Al_0.17As/In_0.83Ga_0.17As红外探测器的倍增层掺杂浓度对器件电场强度、电流特性和光响应度的影响规律。结果表明，随着倍增层掺杂浓度的增加，器件倍增层内的电场强度峰值增加，同时，器件的暗电流与光响应度减小。进一步研究发现，当倍增层掺杂浓度为2×10¹⁶ cm⁻³时，器件获得最优性能，暗电流密度为0.621 44 A/cm²，在波长为1.5 μm时，光响应度和比探测率分别为0.954 4 A/W和1.947 5×10⁹ cmHz^1/2W⁻¹。

Photonic generation of radio-frequency (RF) arbitrary microwave waveform with ultra-wide frequency tunable range based on a dispersion compensated optoelectronic oscillator (OEO) is proposed and experimentally demonstrated. Dispersion compensation scheme and specially designed fiber Bragg grating (FBG)-based Fabry–Perot (F-P) filters are employed in the OEO loop to realize a frequency tunable range of 3.5–45.4 GHz. An optimization process provided by the combination of an erbium-doped fiber amplifier (EDFA) and FBG is employed to improve the signal-to-noise ratio (SNR) of final RF signals. The generation of linear-frequency and phase-coded microwave waveforms, with a tunable carrier frequency ranging from 4 to 45 GHz and tuned chirping bandwidths or code rates, is experimentally demonstrated.

The output amplitude of the differential circuit is studied for differential discrimination in pulsed laser time-of-flight systems. Based on the studies of the probability of detection and the probability of false alarms, the minimum detectable input signal of differential discrimination can be calculated. The results indicate that the differential discrimination detectability of the small signal will be reduced. A combined discrimination is proposed in this Letter to improve the time resolution of the large signal and ensure the probability of detection of the small signal at the same time. A proper value of the circuit parameter is found to balance the time resolutions of the small and large signals.