Dual On-Fiber Thin Film Heaters for Fiber Gratings with Independently Adjustable Chirp and Wavelength

Dual, independently addressable thin film resistive heaters fabricated in a multilayer geometry on the surface of an optical fiber provide a new, flexible means for thermally tuning the properties of intracore gratings. In particular, control of the current applied to each of these heaters enables the chirp and the central wavelength of the grating to be adjusted independently. This letter describes designs and simple fabrication procedures for these types of devices, the important physics of heat flow in them and a tunable add/drop filter that demonstrates essential aspects of their operation.