The behavior of a temperature self-compensating, fiber, long-period grating (LPG) device is studied. This device consists of a single 325-µm-period LPG recorded across two sections of a single-mode B-Ge-codoped fiber—one section bare and the other coated with a 1-µm thickness of Ag. This structure generates two attenuation bands associated with the eighth and ninth cladding modes, which are spectrally close together (~60 nm). The attenuation band associated with the Ag-coated section is unaffected 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 ±1.0 × 10-3 for the refractive index and ±0.3 °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.
Bibliographical note© 2003 Optical Society of America This paper was published in Applied Optics and is made available as an electronic reprint with the permission of OSA. The paper can be http://www.opticsinfobase.org/ao/abstract.cfm?URI=ao-42-19-3766. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law.
- temperature self-compensating fiber
- long-period grating
- attenuation band