Analysis and Design of Corrugated Long-Period Gratings in Silica-on-Silicon Planar Waveguides

A detailed theoretical analysis on light transmission through a corrugated long-period waveguide grating made in a silica-on-silicon planar waveguide is presented. A grating period of ~280 mum is considered in order to achieve a strong rejection band at a wavelength region of 1.5 mum. Phase-matching graphs are studied to find the relationship between the resonance wavelength and the grating period. The effects of the variation of the waveguide and grating parameters on the resonance wavelength are investigated in detail. Polarization dependence on the waveguide gratings is studied, and finally, the design is optimized by proper choice of the grating parameters, which results in a polarization-independent rejection band in the operating wavelength region. This type of waveguide grating has significant potential for various integrated-optic devices and sensing applications.