Picosecond semiconductor lasers based on regenerative feedback schemes

We describe the generation of ultrashort pulses in semiconductor lasers by means of novel regenerative feedback techniques. These new techniques require only relatively simple off-the-shelf electronic components, and circumvent the need for any external RF oscillators for successful picosecond pulse operation of the semiconductor lasers. Pulsewidths as short as /spl sim/10 ps have been obtained by regenerative mode-locking, and repetition rate tunability of /spl sim/200 MHz has been demonstrated (with pulses of /spl sim/35 ps pulsewidth) by regenerative gain switching, as elaborated below.<>