Optical guided-wave gallium arsenide monolithic interferometer

A guided-wave interferometer capable of modulating 1.3-micron radiation via the electro-optic effect has been fabricated in GaAs. The interferometer uses three-guide couplers as the input and output sections and single-mode slab-coupled p(+)-n(-)-n(+) rib waveguides fabricated by means of Be-ion implantation for the two active arms. An extinction of approximately 14.5 dB of the output signal from the center guide is obtained with 22 V applied to one arm of the interferometer. Interferometers of this type should be capable of large signal modulation out to 5-10 GHz.