Vacuum-compatible low-loss Faraday isolator for efficient squeezed-light injection in laser-interferometer-based gravitational-wave detectors

In this paper, we present, to the best of our knowledge, the first low-loss vacuum-compatible thermally controlled Faraday isolator able to retain a good isolation factor under high-vacuum working conditions. The throughput that can be obtained with the developed device is as high as 99%, retaining an isolation factor higher than 40 dB. That very high isolation ratio can be kept over long time periods independently from external temperature conditions with a few Celsius degrees of variation due to thermal active control. The mechanical and optical configuration is detailed, and the performances achieved with this device are presented. (C) 2018 Optical Society of America