title: Theoretical and experimental analysis of excessively tilted fiber gratings.
abstract: We have theoretically and experimentally investigated the dual-peak feature of tilted fiber gratings with excessively tilted structure (named as Ex-TFGs). We have explained the dual-peak feature by solving eigenvalue equations for TM0mand TE0mof a circular waveguide, in which the TE (transverse electric) and TM (transverse magnetic) core modes are coupled into TE and TM cladding modes, respectively. Meanwhile, in the experiment, we have verified that one of the dual peaks at the shorter wavelength is due to the TM mode coupling whereas the other one at the longer wavelength arises from TE mode coupling when a linearly polarized light launched into the Ex-TFG. We have also investigated the peak separation of TE and TM cladding mode for different surrounding medium refractive indexes (SRI), revealed that the dual peaks separation is decreasing as increasing of SRI, which agrees very well with the theoretical analysis results.
authors.forename: Zhijun
authors.initials: Z
authors.lastname: Yan
authors.forename: Hushan
authors.initials: H
authors.lastname: Wang
authors.forename: Changle
authors.initials: C
authors.lastname: Wang
authors.forename: Zhongyuan
authors.initials: Z
authors.lastname: Sun
authors.forename: Guolu
authors.initials: G
authors.lastname: Yin
authors.forename: Kaiming
authors.initials: K
authors.lastname: Zhou
authors.forename: Yishan
authors.initials: Y
authors.lastname: Wang
authors.forename: Wei
authors.initials: W
authors.lastname: Zhao
authors.forename: Lin
authors.initials: L
authors.lastname: Zhang