Feature

Low loss single-mode semiconductor optical waveguides

T. P. Lee

Integrated optoelectronic circuits made of GaAs/AlGaAs and InP/InGaAsP have attracted considerable interest in recent years. Such integrated circuits combine electronic circuitry with lasers, optical waveguide devices, and optical detectors, all on the same semiconductor chip. However, one of the important problems associated with integrated optoelectronics has been the relatively high propagation losses in single (spatial) mode semiconductor optical waveguides. Propagation loss coefficients were ≥ 1 dB/cm for photon energies below the semiconductor band gap. These loss values are about one order of magnitude larger than those achievable in the more well established materials used for integrated optics, most notably lithium niobate. Such high propagation losses are unacceptable for many integrated optoelectronics applications.