Patent ID: 8665447

Claim:
A sensor for sensing variations in at least one parameter, the sensor comprising: (a) an optical device defining two optical paths, at least one of said optical paths being deployed so that the phase accumulated by light propagating along the optical path is affected by a variation in the parameter, said optical paths being arranged to be fed by a common light source and recombining to generate an interference-modulated optical output; and (b) a spectral interrogation arrangement including a radiation input device for delivering to said optical device incident radiation at a plurality of wavelengths, and a reading arrangement for measuring said interference-modulated optical output, wherein said two optical paths pass along spatially-separated first and second waveguides, respectively, and wherein at least part of said first waveguide differs from said second waveguide in at least one property selected from the group consisting of transverse dimension, optical properties of a core material, and optical properties of a cladding material, such that said two optical paths have differing dispersion properties such that a difference between the phase accumulated by light propagating along said optical paths as a function of wavelength exhibits a maximum or minimum at some wavelength designated λcritical, and wherein said plurality of wavelengths span a range of wavelengths including, or adjacent to, λcritical.