Tunable chirped fiber Bragg gratings by a distributed heater

We propose a new design for introducing a tunable chirp on a uniform fiber Bragg grating by a controllable temperature gradient. The device consists of an unchirped Bragg grating in a bare fiber that is mounted in a plastic sleeve whose surface is coiled with a length of wire heater. The desired temperature distribution produces a chirp on the grating and at a rate that can be adjusted by varying the current. We demonstrate an electrically tunable chirped fiber Bragg grating that enables a tuning range of an average chirp rate up to 0.93 nm/cm with an electrical power of 3.3 W. We also demonstrate a tunable chirped fiber Bragg grating in which dispersion is adjustable from -1632 to -667 ps/nm with an electrical power of less than 0.5 W. (C) 2001 Society of Photo-Optical Instrumentation Engineers.