Patent ID: 7421905
Filing Date: 2008-09-09
Classification: G01D,G01K,G01L

Abstract:
1. An optical sensor comprising a launch waveguide and at least two sensing regions located proximate to each other wherein one of the sensing regions is a pressure sensing region having a first and a second reflecting surface, wherein the distance between the first and second reflecting surfaces changes in response to a change in pressure, and wherein a first reflected light and a second reflected light from said reflecting surfaces form an interferometric signal representative of a pressure at the location of the optical sensor, and wherein the reflected lights have substantially the same wavelengths as the original incident light, wherein the other sensing region is a temperature sensing region substantially insensitive to pressure, and wherein the launch waveguide is connected to a housing and when the housing is exposed to a pressure at a predetermined downhole location in an oil or gas well, and the exposure to the downhole pressure changes the dimensions of at least a portion of the housing to change the distance between the first and second reflecting surfaces, such that the pressure and temperature can be measured.