Spectral tailoring of uniform long-period waveguide grating by the cladding thickness control

We propose a new spectral tailoring method applicable to long-period waveguide gratings. It is based on the cladding thickness control along the direction of light propagation. Partially changing the cladding thickness with only a single uniform grating, we can make the core mode coupled to different cladding modes. Hence, almost independent resonance bands are formed in the transmission spectrum. The overall transmission spectrum is tailored by controlling each resonance band. Theoretically, the proposed spectral tailoring method is investigated.