title: Characterization of Long-period Grating Refractive Index Sensors and Their Applications.
abstract: The influence of grating length and bend radius of long-period gratings (LPGs) on refractive index sensing was examined. Sensitivity to refractive indexes smaller than that of silica could be enhanced by bending LPGs. Bent LPGs lost sensitivity to refractive indexes higher than that of silica, whereas a 20-mm-long LPG arranged in a straight line had considerable sensitivity. These experimental results demonstrated that the sensitivity characteristics of LPGs to refractive index could be controlled by grating length and bend radius.
authors.affiliation: Research Institute of Instrumentation Frontier, National Institute of Advanced Industrial Science & Technology, Tsukuba Central 2, Tsukuba 305-8568, Japan; E-Mail:  urabe-k@aist.go.jp.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tsuda
authors.forename: Kei
authors.initials: K
authors.lastname: Urabe