| Title |
Study on Continuous Frequency Tuning of Narrowband Multiwavelength Spectrum Using Successive Combination of Quarter-Wave Retarders of Optical Fiber Comb Filter |
| Authors |
Minchan Bae ; Yong Wook Lee |
| DOI |
http://doi.org/10.5207/JIEIE.2023.37.2.001 |
| Keywords |
Narrowband multiwavelength spectrum; Optical fiber comb filter; Wave retarders; Wavelength tuning |
| Abstract |
We propose an optical fiber comb filter based on a polarization-diversity loop structure, which can continuously adjust the narrowband multiwavelength spectrum. The proposed comb filter consists of a polarization beam splitter(PBS), a successive combination of quarter-wave retarders(QWRs), a set of a half-wave retarder and a QWR, and two polarization-maintaining fiber(PMF) segments of equal length. For the convenient adjustment of the narrowband multiwavelength spectrum, the successive combination of QWRs was located between the PBS and the first PMF segment. The transmittance function of the proposed filter was theoretically derived using the Jones calculus. Based on the filter transmittance, we theoretically predicted the orientation angle sets of four wave retarders, which allow the extra phase difference φ of the transmittance function to vary from 0o to 315o with increments of 45o. Then, the proposed filter successfully demonstrated the predicted results by obtaining ∼0.0915 nm average wavelength shift and a high linearity of 0.99878. |