共振器直交集積導波モード共鳴フィルタの基礎検討

摘要

共鳴波長で鋭い反射を示す導波モード共鳴フィルタに2つの分布ブラッグ反射器（DBR）を集積した共振器集積導波モード共鳴フィルタ（CRIGF）は，微小開口で高効率反射を示す光学フィルタとして検討されている．導波モードの偏光分散により，CRIGFは偏光依存性を示す．今回，偏光無依存化のために，薄膜導波路に2次元グレーティングカップラと4つの湾曲パターンDBRを集積した共振器直交型のC－CRIGFを考案し，理論的実験的に検討している．設計・作製したC－CRIGFを用いて偏光無依存化の可能性を示している．%Cavity-resonator-integrated guided-mode resonance filter (CRIGF) is expected to provide high reflectance and narrow-band spectral response with small aperture. CRIGF consists of a grating coupler located inside a cavity formed by two distributed Bragg reflectors. Crossed CRIGF consisting of two CRIGFs orthogonal to each other was proposed for realization of a polarization-independent CRIGF. Crossed CRIGF was designed and fabricated. Polarization dependence of reflection spectrum of the fabricated crossed CRIGF was measured and the feasibility of polarization-independency was discussed.