Optical Waveguide Intensity Modulators Based on a Tunable Electron Density Multiple Quantum Well Structure.

With a recently developed semiconductor heterostructure it has become possible to tune continuously the electron density in multiple quantum wells. We have demonstrate the first electro- optic waveguide intensity modulators based on this concept. We achieve 22 dB on/off ratio for 9 V applied at 1.54microns wavelength in a rib waveguide electroabsorption modulator. Electrorefractive devices include a waveguide Mach-Zehnder interferometer with active length 650microns operating at 1. 58microns wavelength with 5.4 V half-wave voltage. We show that the operating voltage can be further reduced by operating the Mach-Zehnder modulators in push-pull configuration.