Abstract
The potential of different fiber Bragg grating pairs for simultaneous sensing of strain and temperature is analyzed. We demonstrate that interferometric interrogation of a fiber grating written in bow-tie fiber enables strain and temperature to be simultaneously determined. This is achieved by independent measurement of the shift in the wavelengths of the reflected light from the grating components along the fast and the slow axes of the hi-bi fiber. A detailed theoretical analysis is presented that includes the basic sensing principle, sensor design and demodulation scheme. The performance of the proposed technique in simultaneous measurement of temperature and strain is experimentally demonstrated and resolutions of +/-2.5 degrees C/root Hz and +/-26 mu epsilon/root Hz are obtained for a fiber with birefringence of B = 5.5 x 10(-4). (C) 2000 Society of Photo-Optical Instrumentation Engineers. [S0091-3286(00)00808-4].

Abstract
A compact all-fiber interrogation technique for Bragg sensors is presented. It is based on the generation of an electric carrier by modulating the coupling length of a wavelength-division multiplexer (WDM). Theoretical and experimental results are presented when both serrodyne and sinusoidal modulations are considered. It is shown that this technique provides static microstrain resolution in measurement intervals larger than some millistrain.

Abstract
The interrogation of fiber Bragg grating sensors with multimode laser diodes is theoretically and experimentally analyzed using two different approaches: serrodyne and dithering techniques. It is also demonstrated that by using several laser modes it is possible to enhance the measurement range without compromising sensitivity, (C) 2000 Academic Press.

Abstract
An all fiber interrogation technique for Bragg sensors is presented. It is based on generation of an electric carrier by modulating the coupling length of a wavelength division multiplexer. Results are given when both serrodyne and sinusoidal modulation formats are considered.

Abstract
An all fiber technique for interrogation of interferometric low-finesse Fabry-Perot cavities is presented. It is based on the modulation of the spectral transfer function of a wavelength division multiplexer. Results are given when both serrodyne and sinusoidal modulation formats are considered.

Abstract
Two self-referenced intensity based optical fiber sensors supported on a Michelson sensing head configuration with and without optical feedback are described. Theoretical and experimental studies that demonstrate both sensors are discussed.