Determining Properties of Fabricated Index-Guiding Photonic Crystal Fibers Using SEM Micrograph and Mode Convergence Algorithm

We develop a method for modeling properties of fabricated (realistic) air-silica photonic crystal fibers (PCFs). Our approach involves extracting the transverse refractive index (RI) profile of the drawn PCF from its scanning electron micrograph on which is operated a precise and fast mode-analysis recipe based on a finite difference (FD) field convergence scheme. From the digitized scaled RI distribution, we evaluate propagation characteristics of guided modes of PCFs, examining modal shapes, birefringence, dispersion, and other relevant properties. Naturally, our true-structure study of PCFs using FD algorithm exhibits results that are more close to measured data, establishing its practicality as compared with idealized-structure modeling. To demonstrate the efficacy of our method, we investigate some application-specific experimentally drawn PCFs, well known for their study in the literature. The key results that fairly predict experimental measurements are presented. Besides modeling fabricated fibers, this analysis will be very useful to realize PCFs with targeted specifications using feedback of estimation and characterization of trial fabrications.