High-power and low-noise photodetector for interferometric gravitational wave detectors

We have developed a photodetector for interferometric gravitational wave de tectors which can detect high power light with low intrinsic noise. The det ector is designed to detect a laser power of more than 100 mW at 1.064 mum with a single InGaAs photodiode. Using a resonant circuit, low intrinsic no ise is achieved; the noise-equivalent photocurrent is 132 muA. By using a p hotocurrent limiter used in the circuit, we confirmed that even with high p ower (2 W) incident on the diode, the: diode was undamaged.