title: Influence of cladding-mode coupling losses on the spectrum of a linearly chirped multi-channel fiber bragg grating.
abstract: Influence of cladding-mode coupling losses on the spectrum of multi-channel fiber Bragg grating (FBG) has been numerically investigated on the basis of the extended coupled-mode equations. It has been shown that there exists a reflection slope in the spectrum of both the intra- and inter-channels due to the existences of the cladding modes. This slope could be larger than 1 dB when the induced index change is about 3x10-3, which makes the channels considerably asymmetric. For comparison, a 39-channel linearly chirped FBG with a channel spacing of 0.8 nm and a chromatic dispersion of -850 ps/nm has been designed and fabricated. The experimental results show good agreement with the numerical ones. Finally, one method to pre-compensate the reflection slope within the intra-channels has been proposed and successfully demonstrated.
authors.forename: Hongpu
authors.initials: H
authors.lastname: Li
authors.forename: Yuusaka
authors.initials: Y
authors.lastname: Nakamura
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Ogusu
authors.forename: Yunlong
authors.initials: Y
authors.lastname: Sheng
authors.forename: Joshua
authors.initials: J
authors.lastname: Rothenberg