Monolithic hybrid mode locked 1.3 μm semiconductor laser arrays

The first results for hybrid mode locking of semiconductor lasers are reported. Hybrid mode locking combines both active and passive mode locking to produce shorter mode-locked pulses. These functions are integrated into monolithic devices with a 1.3-μm GaInAsP gain region, an active waveguide, and a saturable absorber. The monolithic mode locked lasers are fabricated as arrays of six devices. These devices have low threshold currents and exhibit hysteresis in their light/current characteristics. The uniformity of threshold currents over an array of devices is very good. The long integrated waveguides allow mode locking at a repetition rate of 15 GHz without the need for an external cavity, with pulse widths as short as 1.4 ps being demonstrated.