Design of Micro Loop Ring Resonator Tunable Filter Based on PCF

By proposing a microloop ring resonator built on photonic crystal fiber (PCF), we presented an analysis of a tunable optical filter by considering steady state response of the resonator with a loop length of about 628 mum. By analyzing macrobending characteristics of PCF, we have shown the influence of their characteristic parameters on the filter response. It is shown that the tunability of the filter is mainly achieved by changing the modulation frequency of the field applied to the resonator. The analyses have shown the sharpness and the depth of the filter response are controlled by the field amplitude and the coupling coefficient of the directional coupler, respectively. The full-width half-maximum of the response strongly depends on the number of field circulations in the resonator loop. With the proposed scheme for optical filter, we achieved FWHM of 0.1 nm.