The Loss Mechanics of Nanoporous Silicon Optical Waveguide for Biochemical Sensors

Nanoporous silicon optical waveguides, which serve as the basic foundation for porous silicon based biochemical sensors, have been fabricated by electrochemical etching and laser local oxidation. By optimizing the porous silicon layers, laser writing power and speed, acceptable optical losses have been achieved. Loss mechanisms include scattering, intrinsic absorption, coupling loss at the fiber interfaces, leakage to the silicon substrate and bending loss. At 1550 nm wavelength, we report a propagation loss of 10− 15 dB/cm, measured using the Fabry Pérot method.