Curved and tapered waveguide mode-locked InGaAs/AlGaAs semiconductor lasers fabricated by impurity induced disordering

Modelocking using curved waveguide devices for low facet reflectivity and using tapered waveguide devices for high output power has been demonstrated. Strong suppression of reflection-seeded secondary pulses was observed for curved waveguides, and increased output power for tapered waveguides. InGaAs/AlGaAs quantum-well semiconductor diode lasers were fabricated using impurity induced disordering. The waveguide has a linear taper from 2.5 mu m to 7.5 mu m width over a 150 mu m distance. The modelocked output pulse energy was increased to 4.1 pJ, compared to 1.8 pJ for a similar 2.5 mu m waveguide untapered device.