Patent ID: 7792392
Filing Date: 2010-09-07
Classification: G01F,G01N

Abstract:
1. A method of sensing a gas at an ambient temperature, comprising: providing an optical fiber, wherein said optical fiber has a core, a wavelength resonant in-fiber optic component provided in said core at a first location, and at least one layer of a material attached to said optical fiber in proximity to said first location, said material being able to absorb said gas at a temperature dependent gas absorption rate, said gas absorption rate increasing when a temperature of said material is increased; propagating a first sensing light in said core at said ambient temperature, said wavelength resonant in-fiber optic component receiving said first sensing light and reflecting a first reflected light having a first resonance wavelength that is dependent on an ambient characteristic of said wavelength resonant in-fiber optic component; propagating a power light in said optical fiber for a defined period of time during which at least a portion of said power light is used to heat said material and cause said material to induce a strain in said optical fiber, said strain changing the ambient characteristic to a changed characteristic; allowing said material to cool to a temperature substantially equal to said ambient temperature after said defined period of time has expired; propagating a second sensing light in said core after said material is allowed to cool, said wavelength resonant in-fiber optic component receiving said second sensing light and reflecting a second reflected light having a second resonance wavelength that is dependent on said changed characteristic of said wavelength resonant in-fiber optic component; determining a difference between said first resonance wavelength and said second resonance wavelength; and using said difference to determine at least one of a presence of and a concentration of said gas.