Patent ID: 7443510

Claim:
A method for monitoring variations to an environmental parameter comprising: providing an interferometer having a gap distance that changes in response to said variations in said environmental parameter; providing light from a light source to said interferometer spanning said gap distance, said light source having a range of wavelengths and said interferometer modulating said light to form modulated light, where characteristics of said modulated light change in response to changes in said gap distance; varying wavelength of said light provided to said interferometer by sweeping said light source through said range of wavelengths from λ 1 to λ 2 , wherein λ 1 and λ 2 are selected so that a first non-sinusoidal intensity output curve is generated from analyzing said modulated light, where said first non-sinusoidal light intensity output curve does not complete a full cycle; identifying not more than one reference point on said first non-sinusoidal light intensity output curve; subsequently repeating said sweeping of said light source provided to said interferometer from λ 1 to λ 2 so that a second non-sinusoidal light intensity output curve is generated that does not complete a full cycle; identifying not more than one reference point on said second non-sinusoidal light intensity output curve that corresponds to said not more than one reference point on said first non-sinusoidal light intensity output curve; observing changes between said reference point of said first non-sinusoidal light intensity output curve and said reference point of said second non-sinusoidal light intensity output curve; and producing an output indicative of variations in said environmental parameter based on said observed changes.