Design and characteristics of periodic Butterworth-like filters using a bow-tie-shaped optical fiber ring resonator

Abstract

The design and characteristics of periodic Butterworth-like passing and blocking filters using a bow-tie-shaped optical fiber ring resonator with two 2 x 2 fiber couplers are presented. Performance parameters, such as the ripple, the contrast, the 3-dB bandwidth, and the maximum output intensity of the Butterworth-like passing and blocking filters, are evaluated. It is found that a completely flat frequency response around the central frequency of the passing band or blocking band can be obtained and that the values of the parameters of the fibers and the couplers for the Butterworth-like passing and blocking filters are only slightly different from those for the first and the second resonances of the transmitted output intensity I 4 .