We investigate low-noise preamplifier solutions for LISA which help convert the laser signals into electrical signals.
In LISA, the laser signals used for picometer-precision metrology are converted into electrical signals by photodiodes. The faint, picowatt-level amplitudes of those laser signals set stringent constraints on the photodiode preamplifier noise.
We investigate preamplifier solutions based on low-noise, discrete transistors that outperform their OpAmp-based counterparts in terms of noise, bandwidth and power consumption. A transistor-based preamplifier is currently being used in prototype units for the LISA Mission.
The goal of the current prototypes is to achieve a Technology Readiness Level of 6, which means reaching the desired preamplifier performance in realistic mission conditions (thermal-vacuum, vibration, irradiation). Once this readiness level is achieved, our efforts will focus on supporting the design and test of the engineering and flight models of the LISA photodiode preamplifiers.