Sensing characteristics of a novel two-section long-period grating

Thomas Allsop, Ron Neal, Domenico Giannone, David J. Webb, Des J. Mapps, Ian Bennion
2003 Applied Optics  
The behavior of a temperature self-compensating, fiber, long-period grating ͑LPG͒ device is studied. This device consists of a single 325-m-period LPG recorded across two sections of a single-mode B-Ge-codoped fiber-one section bare and the other coated with a 1-m thickness of Ag. This structure generates two attenuation bands associated with the eighth and ninth cladding modes, which are spectrally close together ͑ϳ60 nm͒. The attenuation band associated with the Ag-coated section is
more » ... by changes in the refractive index of the surrounding medium and can be used to compensate for the temperature of the bare-fiber section. The sensor has a resolution of Ϯ1.0 ϫ 10 Ϫ3 for the refractive index and Ϯ0.3°C for the temperature. The effect of bending on the spectral characteristics of the two attenuation bands was found to be nonlinear, with the Ag-coated LPG having the greater sensitivity.
doi:10.1364/ao.42.003766 pmid:12868812 fatcat:5gh63om5ojcanf7yk4ldktrsry