| Summary: | A ring-waveguide coupled with a silver block is investigated detailedly. The Coupled-Mode theory (CMT) is introduced to analyze the transmission properties, and the CMT result has been demonstrated by the Finite-Difference Time-Domain (FDTD). The result indicates that the lateral displacement S plays an important role in spectrum. At the same time, due to symmetry breaking, a Fano resonance, originating from degenerate interference, can be observed. Owing to the fact that a silver block enhances the interaction between light and matter, the maximum sensitivity is up to 1650 nm/RIU with a FOM of 284.5. The results show that there is a great improvement in sensitivity to introduce a silver block. In addition, when the structure is infiltrated with ethanol, the sensitivity dλ/dT can achieve 0.671 nm/°C and the sensitivity of long wavelength is higher than that of short-wavelength. These excellent features may be applied in temperature sensing. This structure has the advantages of simple and compact, and it has potential applications in nano sensor and highly photonic integrated circuits.
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