Asymmetric fiber taper for narrow linewidth comb filter

The employment of asymmetric optical fiber taper as a means for producing narrow linewidth comb filter is proposed and demonstrated. fiber taper with different values set for the up-taper and down-taper transition regions was used to produce narrow linewidth comb filter through coupling interaction of light in the asymmetric fiber. two configurations; single-pass and bidirectional fiber taper filters were studied and analyzed in this project. results showed narrower 3-db linewidth for asymmetric taper compared with uniform taper for single pass configuration. the asymmetric taper linewidth was improved further in bidirectional configuration,narrowing down to 2 nm. bidirectional asymmetric taper filter recorded extinction ratio of 27.14 db,which was 18 db and 3 db better than single-pass asymmetric taper and bidirectional uniform taper respectively. the findings emphasize the attractiveness of bidirectional asymmetric taper as a high performance optical filter. © 2016 penerbit utm press. all rights reserved.