Backscattering in Silicon Photonic Devices

We investigate the eects of backscattering induced by waveguide sidewall roughness in high-index contrast integrated photonic circuits. Backscattered power is experimentally observed in silicon on insulator optical nanowires, showing its dependence on the waveguide geometrical and optical parameters, and in micro-rings, demonstrating that in an optical resonator the backscattering is enhanced according to the square of its quality factor. From our results, backscattering emerges as one of the most severe impairment in densely integrated photonic devices, capable to dramatically affect their expected behaviour.