Generation of ultrashort light pulses in a semiconductor with a double feedback loop

A semiconductor injection laser with optical and optoelectronic feedback loops was investigated. Active mode locking of such a laser resulted in generation of picosecond light pulses at a repetition frequency dependent on the ratio of the signal transit times in the optical and optoelectronic feedback loops. The results indicated that it should be possible to construct a compact self-contained source of ultrashort light pulses without recourse to sophisticated electronic equipment.