A wideband low-noise pulsed laser detection circuit for the 3D imaging lidar

Abstract

In order to enhance the measurement precision and detection range of the 3D imaging lidar (light detection and ranging), we propose a new broadband low-noise detection circuit for the pulse laser, which mainly includes a high-speed APD (Avalanche Photodiode) detector and a broadband low-noise transimpedance amplifier. In the detection circuit, a high negative bias voltage is applied to the APD detector and used to set the static input current of the amplifier NE5210 to 200 μA with a proper bias method. By this bias method, the allowable input current range of the amplifier NE5210 is enhanced by about 1 time. This paper introduces the main framework and performance of the detection circuit. The output noise voltage, output signal voltage and voltage SNR (Signal-to-noise Ratio) of the detection circuit are analyzed and calculated as well. Some experiments have been carried out with the proposed detection circuit, showing that the detection circuit can detect a narrow pulse laser with about 4 ns pulse width. Based on our experiments and analyses, the pass band of the detection circuit ranges from 0.56 MHz to 200MHz approximately, the allowable input current of the amplifier NE5210 varies from -460 μA to 0, and the effective output differential voltage ranges from -1.6 V to 1.4 V. The proposed detection circuit is implemented and tested in a high-speed 3D imaging lidar. As well as 3D imaging lidars, the detection circuit can be applied to the pulse laser range finder and other pulse laser detection system.