Design and analysis of nano-deep corrugated waveguide grating-based dual-resonant filters in visible and infra-red regions

A theoretical analysis of nano-deep corrugated long-period waveguide gratings on a SU-8 polymer-based channel waveguide with NOA61 optical epoxy coated upper- and lower cladding is presented. The transmission spectra of the gratings show strong rejection bands both at visible (at wavelength region of 450⿿460 nm) and infra-red (at wavelength region of 1530⿿1540 nm) regions when a grating period of ⿼68 μm with optimized grating tooth height is considered. Phase-matching graphs are studied to find the relationship between resonance wavelength and grating period. These results show that the grating parameters significantly affect the characteristics of transmission spectra as well as the resonance wavelength of the grating. Long-period waveguide grating-based band pass filter made by use of same polymer materials are also designed and analyzed. These types of waveguide grating-based filters can widely be used for visible and infra-red wavelength sensing applications.