On the InGaAs-based Photodetection Circuit for Scanning Near-Infrared Signal in the Wavelength Range of 1.0-2.0μm

Abstract

Detection of scanning long wave near-infrared (NIR) signal is critical in numerous applications spanning the fields of military, industry, agriculture, environment, and medicine. In this paper, we present a low cost, high performance InGaAs-based photoelectric conversion and amplification circuit for detecting scanning NIR signal in the wavelength range of 1.0-2.0 μm. With a special focus on reducing the influence of dark current and dark current noise for improved detector efficiency and precision, this proposed circuit features a photovoltaic preamplifier, a low-pass filter, and a temperature control unit; the signal gain, the bandwidth and the noise of the entire circuit is tuned for the signal spectrum of interest. In particular, to make the InGaAs detector operate at the target temperature with little fluctuation, a low-cost closed-loop temperature control circuit is designed that delivers temperature control accuracy of ±0.1°C. Both simulation and experimental results have confirmed that the proposed detection circuit meets the specific performance requirements for its intended use in spectrometer.