title: Analysis of inverse-Gaussian apodized fiber Bragg grating.
abstract: Inverse-Gaussian apodized fiber Bragg gratings (IGAFBGs) are numerically studied using the transfer matrix method and fabricated by the commonly used phase-mask scanning technique in a single-step scanning process. The IGAFBG can serve as a dual-wavelength passband filter, whose wavelength spacing can be continuously tuned by introducing a tunable chirp through applying a strain gradient in principle. Also, an IGAFBG with identical dual passbands having 0.144nm wavelength spacing is experimentally achieved. We also show that an IGAFBG can act as a multipassband filter with varied free spectral ranges (FSRs), and the largest FSR variation of this IGAFBG is nearly seven times more than that in a comparable FBG pair filter. An IGAFBG with varied FSRs of approximately 16.125, approximately 12.25, approximately 8.5, and approximately 6.375GHz is fabricated. This multipassband varying-FSR IGAFBG filter can find applications in step-tunable microwave generations.
authors.affiliation: Photonics Research Centre, School of Electrical and Electronic Engineering, Nanyang Technological University,50 Nanyang Avenue, Singapore 639798, Singapore.
authors.forename: Bo
authors.initials: B
authors.lastname: Lin
authors.forename: Swee Chuan
authors.initials: SC
authors.lastname: Tjin
authors.forename: Nam Quoc
authors.initials: NQ
authors.lastname: Ngo
authors.forename: Yufeng
authors.initials: Y
authors.lastname: Song
authors.forename: Sheng
authors.initials: S
authors.lastname: Liang
authors.forename: Li
authors.initials: L
authors.lastname: Xia
authors.forename: Meng
authors.initials: M
authors.lastname: Jiang