本論文中，將使用波導光柵的結構來設計高品質因數折射率感測器，這種結構是由波導模態共振效應與表面光柵結合。其中，波導模態效振效應會使入射光入射至光柵之中時產生出繞射光，則繞射光會在波導層之中激發出TE/TM 的波導模態，且被光柵結構所激發的模態會在傳播一段距離之後洩漏出去，當兩道洩漏的繞射光相位匹配時，就會有共振產生。 利用Rsoft Diffrac MOD模擬軟體進行模擬及分析一維波導光柵結構，並在結構上覆蓋一層高折射率薄膜。在覆蓋薄膜之後，會讓靈敏度減少從260.1至251.9(nm/RIU)下降了3.15%但因為光柵層的等效折射率增加，則能量更加地集中在結構之中，然而半峰全寬（Full width at half maximum，FWHM）就會變得更窄，TM模態的FWHM從原本1.8 × 10-3nm變窄至3 × 10-4nm，使變窄的FWHM讓品質因數(Figure of Merit，FOM)從144500(1/RIU)增加到839666(1/RIU)提升了481%。 在透過電場圖得知當改變結構參數，會因等效折射率提升和束縛模態與輻射模態之間的正交關係，使電場能量從一開始分散在結構之中變成侷限在等效波導層之中進行傳遞。 ;In this paper, we combine the waveguide mode resonance effect with a surface grating structure called a waveguide grating to design a high figure of merit refractive index sensor. When the incident light is incident on the grating, the diffracted wave will be generated, and the diffracted wave will excite the TE/TM waveguide mode in the waveguide layer, and the mode excited by the grating structure will leak out after propagating for a certain distance. When the phases of the two leaked diffracted waves are matched, resonance will occur. Using Rsoft Diffrac MOD simulation software to simulate and analyze the one-dimensional waveguide grating structure, and cover the structure with a high refractive index film. After covering the film, the sensitivity reduction decreases by 3.15% from 260.1 to 251.9 (nm/RIU), but because the equivalent refractive index of the grating layer increases, the energy is more concentrated in the structure, while the full width at half maximum ( Full width at half maximum, FWHM) will become narrower, and the FWHM of the TM mode is narrowed from 1.8 × 10-3nm to 3 × 10-4nm, making the narrowed FWHM lower the quality factor (Figure of Merit, FOM). ) increased from 144500 (1/RIU) to 839666 (1/RIU) by 481%. It can be seen from the electric field diagram that when the structural parameters are changed, due to the increase in the effective refractive index and the orthogonal relationship between the bound mode and the radiation mode, the electric field energy will be dispersed in the structure from the beginning to confined in the effective waveguide transfer between layers.
