Electrically tunable efficient broadband long-period fiber grating filter

Summary form only given. We present a new type of the tunable optical fibre filter based on a metal coated long period grating (LPG) written in a specially-developed fiber containing air regions inside the cladding. The air regions are filled with polymers with high temperature sensitivity resulting in broadband tuning range and high electrical heating efficiency. These new structures are attractive because they are practically insensitive to the variations of the refractive index of the surroundings, and thus can be coated by metal with no measurable changes in the transmission spectrum.