Tunable Narrowband Filter Based On A Combination Of Fabry-Perot Etalon And Volume Bragg Grating

A new type of tunable narrowband filter is proposed. This filter is a combination of a Fabry-Perot etalon, which permits the selection of a comb of discrete narrow bands, and a high-efficiency rotating volume Bragg grating recorded in photo-thermo-refractive glass, which permits tuning between the Fabry-Perot resonances. A tunable filter for fixed wavelengths in the region of 1.5 μm with a spectral width of 220 pm (FWHM), separation between channels of 800 pm, and throughput of 95% (losses \u3c0.2 dB) is demonstrated. © 2006 Optical Society of America