Low-bias-current direct modulation up to 33 GHz in GaAs-based pseudomorphic MQW ridge-waveguide lasers suitable for monolithic integration

Abstract

The successful application of direct laser modulation for very-high-speed digital transmission or microwave/millimeter-wave analog optical links requires a) reductions in the drive currents required to achieve high modulation bandwidths, b) increases in the maximum intrinsic modulation bandwidths, c) reductions in laser chirp under high-speed direct modulation, and d) high-speed laser structures which can be monolithically integrated with high-speed transistors. Utilizing a single epitaxial growth (HEMT+laser) and an air-bridged, coplanar electrode geometry, a complete technological process has also been developed in our labs for the monolithic integration of vertically-compact GaAs MQW ridge-waveguide (RWG) lasers with double pulse-doped GaAs/AlGaAs QW enhancement/ depletion HEMT electronics.