High Sensitivity Picosecond Optical Pulse Detection by Semiconductor Laser Amplifiers Via Cross-Correlation

Abstract

A novel method to measure the temporal behaviour of ultrashort light pulses is presented. A semiconductor laser amplifier driven by short injection current pulses presents the light sensitive device in a cross-correlation experiment. The method is based on the picosecond temporal response of the gain of the semiconductor laser amplifier driven by short injection current pulses. Computer simulations show that the time resolution is better than 10 ps under appropriate injection conditions. This prediction is confirmed by experiments where a GaA1As-twin-channel-substrate-mesa-guide laser amplifier is used to study ps-pulses of a current modulated multiple quantum well laser. Our results prove that the cross-correlation method is at least one order of magnitude more sensitive than the conventional method of detection by the combination of a fast photodiode and a sampling scope.