Observation of ultrashort (<4 ps) gain-switched optical pulses from long-wavelength multiple quantum well lasers

Abstract

Optical pulses of less than 4 ps full width at half maximum have been generated by electrical gain switching of long-wavelength multiple quantum well lasers, and were observed directly on a streak camera. This is the first ever generation of optical pulses of such short duration using direct electrical gain switching. We have identified the higher differential gain due to the second quantized state transition in the multiple quantum well laser to be responsible for the generation of these ultrashort optical pulses. We also discuss the possible resolution limits of the streak camera measurement system.