A Low-Power, Low-Noise 37-MHz Photoreceiver for Intersatellite Laser Interferometers Using Discrete Heterojunction Bipolar Transistors

摘要

Intersatellite laser interferometers feature quadrant photoreceivers to produce electrical signals from the interfered optical beams. In the particular case of Laser Interferometer Space Antenna, the expected optical ac beat note has an amplitude of the order of nanowatts. This requires photoreceivers with an input current noise density of a fewn${mathrm {pA}} cdot {mathrm {Hz}}^{-1/2}$nin each channel up to 25 MHz. In addition, the significant number of photoreceivers in a single spacecraft imposes tight constraints on the power consumption per device. We present the experimental characterization of a quadrant photoreceiver based on discrete heterojunction bipolar transistors and an off-the-shelf 0.5-mm-diameter InGaAs quadrant photodiode, showing an input current noise density of 1.9n${mathrm {pA}} cdot {mathrm {Hz}}^{-1/2}$nat 25 MHz, a 3-dB bandwidth of 37 MHz, and a total power consumption of 178 mW.