Ultra-sensitive autocorrelation of 1.5 μm light with single photon counting silicon avalanche photodiode

Abstract

1.5 µm two-photon absorption in a single photon counting silicon avalanche photodiode at record continuous-wave levels below 100 µW is reported. Autocorrelation of a 10 GHz, 1.67 picosecond pulsetrain using this device demonstrates 1.5×10−3 (mW)2 peak-power times average-power sensitivity without the use of lock-in detection.