A compact four-peak MIM filter based on asymmetric distribution of resonators

We theoretically propose and numerically analyze a compact Metal-Insulator-Metal(MIM) filter based on an asymmetric structure which can produce four peaks in the spectrum. The filter can generate four transmission peaks while the maximum transmission coefficient of each peak is above 90%, and each transmission peak can be individually tuned by changing the coupling angle between the resonators and the waveguide. The structure consists of a pair of asymmetric cavities above and below the waveguide. By adjusting the coupling angle between the cavities and waveguide, each cavity can filter out light of a specific wavelength. The transmittance of the lowest transmission peak could be 3% and each transmission peak has a narrow frequency width. The quality factor (Q) of the resonances are 29.5, 42.9, 17.3 and 77.1, respectively. The sensitivities are 500nm/RIU, 588 nm/RIU, 659 nm/RIU and 827 nm/RIU. The FOMs are 26.3, 39.2, 15.3, 75.2. Multimode interference coupled-mode theory (MICMT) is used for numerical calculation and theoretical analysis. The structure is compact and easy to be fabricated and has potential applications in nano-optical communication.

Automated summary

This study proposes a compact Metal-Insulator-Metal (MIM) filter that can generate four transmission peaks with high transmission coefficients and narrow frequency widths. Each transmission peak can be individually tuned by adjusting the coupling angle. The structure of the filter is compact, easy to fabricate, and has potential applications in nano-optical communication.