Mode looking of semiconductor lasers is a potentially attractive technique to generate short optical pulses for telecommunications and signal processing applications. Short, high peak power pulses will be especially important for very high bit rate lightwave systems. Active mode locking of semiconductor lasers has previously been achieve by modulating the gain of the active medium and using a passive extended cavity.1 Here we propose and demonstrate a mode-locked laser that incorporates a 2 × 2 broadband Ti:LiNbO3 electrooptic waveguide directional coupler switch as an integral part of the cavity. The waveguide switch has low loss and is fiber-coupled to the AR-coated facet of an InGaAsP/InP laser diode. By driving the switch with a sinusoidal signal, we have produced a train of 22-psec wide (FWHM) mode-locked pulses at a 7.2-GHz repetition rate.
© 1984 Optical Society of AmericaPDF Article