title: Index profiling of anisotropic graded-index planar waveguides from effective indices.
abstract: We present a method for recovering the refractive-index profile of an anisotropic graded-index waveguide from the effective indices by using a cubic spline interpolation function. The first and second derivatives of cubic splines are continuous to ensure a smooth index profile, which is consistent with practical graded-index distributions. A straightforward iteration with an exact dispersion equation to verify the interpolated profile makes this method easy and reliable for application. This approach is proved by numerical analysis of several typical index distributions and experimental examples showing that the refractive-index profiles in anisotropy can be reconstructed close to the exact profile. Waveguides with both more modes (more than four guiding modes) and fewer modes (two to four) can be universally profiled with good accuracy.
authors.affiliation: Institute of Optics and Photonics, Department of Physics, State Key Laboratory on Fiber-Optic Local Area Communication Networks and Advanced Optical Communication Systems, Shanghai Jiao Tong University, 800, Dong Chuan Road, Shanghai 200240, China.
authors.forename: Weijun
authors.initials: W
authors.lastname: Liao
authors.forename: Xianfeng
authors.initials: X
authors.lastname: Chen
authors.forename: Yuping
authors.initials: Y
authors.lastname: Chen
authors.forename: Yuxing
authors.initials: Y
authors.lastname: Xia