Optical losses in porous silicon waveguides in the near-infrared: Effects of scattering

Benefitting from the long path inside planar waveguides, we have investigated the optical losses of porous silicon, in the continuous 0.8–1.6 μm (0.77–1.55 eV) range. The obtained values, typically a few cm−1, are 1 order of magnitude larger than “pure” absorption losses measured previously. The other main sources of loss, including scattering on both interface roughness and nanocrystallites, are invoked. Calculations give the same order of magnitude as measurements. We also detected scattered light close to the direct beam.