In-line devices and sensors based on air-silica microstructure optical fibers

This paper reports some of our recent work on in-line devices based on air-silica microstructrue optical fibers. These devices are fabricated by use of a CO 2 laser/a femtosecond infrared laser and include strong long period gratings in index-guiding fibers and air-core photonic bandgap fibers, in-fiber polarizers, polarimeters, and modal interferometers. Applications of such devices for strain, temperature, directional bend, twist, and gas sensing are discussed.