Analysis of a fiber Bragg grating writing process using low-coherence interferometry and layer-peeling

Abstract

We demonstrate accurate measurements of the longitudinal refractive index profile of a fiber Bragg grating (FBG). We measure the impulse response of a FBG with a low-coherence interferometer, calculate the complex spectrum from a Fourier transform of the interferogram, and then apply a layer-peeling algorithm to find the index profile of the measured FBG. We use our results to calibrate and identify systematic errors in a scanning beam/dithered phase mask FBG writing system.