Abstract

Long-period gratings are now being used as gain equalizers in broadband amplifiers¹ and as band-rejection filters in a variety of applications.² While these devices provide elegant in-fiber solutions to many problems in fiber communications, they can exhibit high temperature sensitivities if sufficient care is not taken in their design. When written in conventional communication-grade fibers, their spectra can shift by 4 - 10 nm per 100°C change in temperature. Two solutions to this problem have been successfully demonstrated using specially designed fibers, one based on tailoring the fiber refractive index profile³ and the other based on the use of appropriate dopant materials in the core.⁴ In this paper, we present long-period gratings written in conventional communication-grade fibers that use the properties of a specially-designed polymer recoat to provide the temperature-independent performance.

© 1997 Optical Society of America