INGAAS INALAS QUANTUM-WELL ELECTROABSORPTION WAVE-GUIDE MODULATORS WITH LARGE-CORE WAVE-GUIDE STRUCTURE - DESIGN AND CHARACTERIZATION/

The design and the systematic characterization of the waveguide and th e material properties of a modulator based on InGaAs/InAlAs quantum-we ll material for 1.5-mu m operation are described. Following our previo usly developed theoretical design algorithm for optimizing the total p erformance of waveguide electroabsorption modulators [IEEE J. Quantum Electron, 29, 2476 (1993)], we designed an unconventional waveguide st ructure with a large passive core to yield better coupling efficiency for standard optical fibers and a thin active layer that yields a smal l optical-confinement factor. To evaluate the performance of this wave guide modulator, experimental methods for measuring the coupling effic iency, the optical-filling factor, and the absorption coefficient of t he waveguide modulator and for characterizing the material properties were developed. The limitations of the material and the waveguide desi gn, and the generalization of the limited set of experimental results based on a specific modulator to the design of more-general waveguide modulators are discussed.