Porous Silicon Optical Waveguides

Abstract

Porous silicon optical waveguides have attracted attention for applications ranging from optoelectronics to chemical and biological sensors. This updated chapter describes various waveguide geometries that have been achieved in porous silicon, including single-and multilayer architectures. Depending on the processing parameters, oxidized porous silicon waveguides can be fabricated with losses below 0.5 dB/cm. While these losses are a challenge for some optoelec-tronics applications, sensor applications of porous silicon waveguides have flourished. Recent innovations have led to demonstrations of the label-free detection of nucleic acid molecules, proteins, and toxins with sensitivities as low as 10 À6 /RIU. In addition, waveguide-based structures such as microring resonators have shown promising nonlinear optical effects. Keywords Mode • Nonlinear • Sensor • Waveguide Contents