Abstract

A concept for optical temperature sensing based on the differential spectral reflectivity/transmittance from a multilayer dielectric edge filter is described and demonstrated. Two wavelengths, λ₁ and λ₂, from the spectrum of a broadband light source are selected so that they are located on the sloped and flat regions of the reflection or transmission spectrum of the filter, respectively. As temperature variations shift the reflection or transmission spectrum of the filter, they change the output power of the light at λ₁, but the output power of the light at λ₂ is insensitive to the shift and therefore to the temperature variation. The temperature information can be extracted from the ratio of the light powers at λ₁ to the light at λ₂. This ratio is immune to changes in the output power of the light source, fiber losses induced by microbending, and hence modal-power distribution fluctuations. The best resolution of 0.2 °C has been obtained over a range of 30–120 °C. Based on such a basic temperature-sensing concept, a wavelength-division-multiplexed, temperature-sensing system is constructed by cascading three sensing-edge filters that have different cutoff wavelengths along a multimode fiber. The signals from the three sensors are resolved by detecting the correspondent outputs at different wavelengths.

© 1995 Optical Society of America

Split-spectrum intensity-based optical fiber sensors for measurement of microdisplacement, strain, and pressure

Anbo Wang, Mark S. Miller, Angela J. Plante, Michael F. Gunther, Kent A. Murphy, and Richard O. Claus
Appl. Opt. 35(15) 2595-2601 (1996)

Erbium-doped silica fibers for intrinsic fiber-optic temperature sensors

E. Maurice, G. Monnom, B. Dussardier, A. Saïssy, D. B. Ostrowsky, and G. W. Baxter
Appl. Opt. 34(34) 8019-8025 (1995)

High-resolution distributed temperature sensing with the multiphoton-timing technique

M. Höbel, J. Ricka, M. Wüthrich, and Th. Binkert
Appl. Opt. 34(16) 2955-2967 (1995)

Progressive ladder network topology combining interferometric and intensity fiber-optic-based sensors

A. B. Lobo Ribeiro, R. F. Caleya, and J. L. Santos
Appl. Opt. 34(28) 6481-6488 (1995)

Optical fiber bundle displacement sensor using an ac-modulated light source with subnanometer resolution and low thermal drift

Atsushi Shimamoto and Kohichi Tanaka
Appl. Opt. 34(25) 5854-5860 (1995)