Abstract

The coupled waveguide optical modulator/switch (the electrically switched optical directional coupler) is one of the most important components in guided-wave and integrated optics, and several device structures for GaAs-based or InP-based semiconductors have been devised^[1-11]. All of them are based on the electrooptic effect in the depletion region of the reverse-biased pn junction or Schottky contact. Among them, a double-heterostructure (DH) device with pn junction in strip-loaded channel waveguide configuration as shown in Fig.1 is expected to have the lowest modulating voltage and modulating power per bandwidth P/∆f because of the most efficient overlap of the modulating electric field with the optical field ^[4,12]. Similar but homostructure devices were fabricaed by Carenco and others ^[13,14]. Recently GaAs-Al_0.04Ga_0.96As DH devices with nearly full switching characteristics have been fabricated for the first time ^[10].

© 1984 Optical Society of America