Patent ID: 7099015

Claim:
A fiber optic sensing device for measuring a physical parameter comprising: a polychromatic light source, generating light over a wide optical spectrum; a fiber optic measuring probe for modulating said polychromatic light, said fiber optic measuring probe having an optical path which is changed with said physical parameter; a normalization probe for attenuating said polychromatic light, said normalization probe having an attenuation approximately equal to an attenuation of said fiber optic measuring probe; an optical spectrometer means for determining a measurement spectrum of said modulated light and a normalization spectrum of said attenuated light; fiber optic means for coupling said modulated light from said fiber optic measuring probe and for coupling said attenuated light from said normalization spectrum to said optical spectrometer; a signal processing means for calculating a normalized spectrum from said measurement and normalization spectrums, for calculating a phase of said normalized spectrum to determine the optical path of said fiber optic measuring probe, and for calculating the value of said physical parameter.