Abstract

External modulators based in GaAs are potentially useful for fiber-optic systems and high-speed signal processing. In contrast to LiNbO₃ devices, a negligible photorefractive effect is observed for wavelengths near 0.8 μm, and GaAs modulators can be monolithically integrated with semiconductor lasers. Over the past few years, a number of GaAs modulators which incorporate AlGaAs/GaAs multiquantum well (MQW) structures have been demonstrated. Wood and co-workers¹ recently reported a MQW modulator with a 131-ps impulse response and on/off ratio of 1.7:1 when light was propagated perpendicular to the MQW layers. To achieve better extinction, they also developed a waveguide modulator in which the light propagated parallel to the MQW layers.² Extinction of 10:1 was achieved when the modulator (150 μm long) was driven from 7 to 11 V.

© 1986 Optical Society of America