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A simple scheme is reported for generating picosecond optical pulses from injection lasers based on short electrical pulse excitation. An integrated step recovery diode impulse-train generator (‘comb’ generator) which gives 50 ps 25 V electrical pulses at 200 to 500 MHz rates is used to drive the injection lasers. Optical pulses as short as 40 ps are generated by the corresponding electrical drive pulses.

By incorporating two quantum wells into a capillary waveguide, we have made the first MQW optical modulator with an on/off ratio of at least 10:1. Furthermore, this device was used to generate an optical pulse less than 100 ps long, the fastest to date with an MQW device.

Nanosecond pulses from an AlGaAs injection laser have been used to optically pump an ultrashort-cavity InP laser. Subnanosecond pulses from the InP laser exhibit a single longitudinal mode at 0.92–0.93 μm.

The letter describes a new scheme for generating repetitive picosecond laser and electrical pulses in a controlled manner. The arrangement is a feedback loop containing a semiconductor diode laser, a photodetector, an amplifier and a time delay. The loop allows the laser to be driven by an ultrashort current pulse derived from the previous laser pulse. Optical and electrical pulses of less than 100 ps have been generated using GaAs-based lumped components. Monolithic integration of these components on a chip seems feasible with possible increase in speed.