Effect of Spherical Aberration on Fabrication of Fiber Bragg Gratings

Abstract

Cylindrical convex lenses are commonly used in fabricating fiber Bragg gratings (FBGs) by the phase mask method to increase the energy fluence of UV laser light and thereby enhance FBG productivity. We have found that lens aberrations can affect the efficiency of FBG fabrication by this method. Comparisons of the experimental measurements of FBG transmission minimum as a function of fiber position during irradiation by focussed excimer laser light with ray tracing calculations demonstrate the effect of spherical aberration, particularly for lenses with shorter focal lengths.