Subpicosecond pulse generation by a tandem-type AlGaAs DH laser with colliding pulse mode locking

Experimental results of colliding pulse mode locking (CPM) of a double-contact AlGaAs DH injection laser with an external cavity are presented. The laser has two amplifying sections and a passive umpumped segment located between them which exhibited saturable absorption action. Ultrashort pulses propagating in opposite directions collided in the absorber and pulse shortening occurred. Bursts of 0.8 ps (FWHM) pulses at a 710 MHz repetition rate are obtained by means of CPM. The pulse duration is measured by a second harmonic generation correlation method and an ultrafast streak camera.