Refractive Index Profiling of Optical Fibers using Low-Coherence Interferometry

Abstract

This thesis is devoted to measure the base refractive index and refractive index profiling of optical fiber We begin by introducing the fundamental theory of optical fiber to analyze and compare with experimental results With optical coherence we build a low-coherence interferometric system If we know the numerical aperture of test fiber we can use cross-correlation between two beams to measure the modal contents such as modal weights profiles effective refractive index and so on Finally we try to reconstruct the two-dimensional refractive index profile from an inverse algorithm Theoretically the profiles of each mode should yield the same refractive index profile of fibers and we can obtain the accurate value by averaging the results In experiment we measure step-index multimode fibers by this system There are some problems in this experiment such as modes are excited incompletely interference is imperfect We conclude that the setup need to be improved but we think this method is feasible

Date of Award	2015 Jul 24
Original language	English
Supervisor	Shuo-Yen Tseng (Supervisor)