Low-loss GaAs <i>p</i>+<i>n</i>−<i>n</i>+ three-dimensional optical waveguides

Abstract

Two types of low-loss single-mode p+n−n+ GaAs three-dimensional waveguides have been successfully fabricated and their attenuation coefficients measured. The devices are an optical stripline and a new device, the channel-stop strip guide. The channel-stop strip guides have losses of 0.8 cm−1 at 1.06 μm and 1.1 cm−1 at 0.920 μm; the losses for the optical striplines are 1.2 cm−1 at 1.06 μm and 1.7 cm−1 at 0.920 μm. A first-order loss calculation has yielded attenuation coefficients within 25% of these measured values. Both structures have an n+ substrate, an n− epitaxial layer for guiding, and p+ regions to laterally confine the light. The p+ regions have a uniform concentration and are formed by multiple-energy Be+-ion implantation; the p+n− junctions show sharp high-voltage breakdowns at average electric fields in the n− layer of 1.5×105 V/cm.