High-rejection–low-loss single-passband filters have been successfully fabricated by the chirped-grating concatenation method in a cladding depressed fiber. The enhanced photosensitivity, the enlarged bandgap between the Bragg resonance and the cladding modes, and the effective suppression of the cladding-mode outcoupling of the cladding depressed fiber permitted what is to our knowledge the first achievement of an ~1-dB loss in the passband and 50-dB rejection for a 50-nm-wide stop band covering the entire amplified spontaneous emission spectral range of an Er-doped fiber amplifier.
© 1998 America
(060.2340) Fiber optics and optical communications : Fiber optics components
(060.4510) Fiber optics and optical communications : Optical communications
(160.2290) Materials : Fiber materials
L. Zhang, Y. Liu, I. Bennion, K. Sugden, and L. Dong, "Fabrication of high-rejection low-loss single-passband filters in cladding depressed fiber by the chirped-grating concatenation method," Opt. Lett. 23, 1665-1667 (1998)