Optimization of detector arrays and circuits targeted for precision calculation in infrared laser interferometer

A low noise transimpedance amplifier (TIA) is used in a wide band PIN (Positive Intrinsic Negative) laser detector arrays to transform the photo current produced by an infrared interfering laser power to an output voltage with a specified amplitude and frequency response. In this paper we consider the specifications of a PIN detector array coupled with a TIA circuit. Then the following issues that influence high precision calculation results will be investigated: low noise performance of the detector array and TIA pre-amplifier; fluctuation effects of amplitude caused by frequency modulation interfering signal; photosensitive area (PA) of the detector and physical distance between detectors. We find that noise performance related with signal to noise ratio (SNR) defines the minimum calculation error. And PA related with sensitivity has influence on junction capacitance and amplitude fluctuation. Meanwhile bias circuit mode related with dark current also influence amplitude response. Based on these issues, a PIN detector array pair is constructed of five sensors arranged in cross. The center response wavelength of the detector array is around 850 nm according to the requirement of the referential laser interferometer.