ELECTROABSORPTION AND ELECTROOPTIC MODULATION IN SINGLE-CRYSTAL ZNSE-ZNSSE WAVE-GUIDES GROWN BY OMPVE ON GAAS

We have used electroabsorption and the electrooptic effect to modulate argon laser light in ZnSe single crystal waveguides. The electrical contacts we used were Schottky barriers that created a nonuniform electric field in the samples. The nonuniform electric fields are modeled here and the experimental results are matched to this model. The electroabsorption experiments have shown a modulation depth of 9.2 dB at an applied voltage of 255 V and a wavelength of 476 nm. With the same applied voltage at lambda = 488 nm the modulation depth was only 0.53 dB. Electrooptic phase modulation was also investigated. We found a phase shift of pi at 60 V for a sample of 3 mm length. The half wave voltage was independent of wavelength for wavelengths from 488 to 515 nm. Finally, we observed a form of rectified optical modulation due to the Schottky barrier depletion regions and electroabsorption in the waveguide.