Patent ID: 7138621
Filing Date: 2006-11-21
Classification: G01D,G01L,G02B

Abstract:
1. A method for determining a pressure and a temperature comprising the steps of: applying light to a first core of an optical fiber such that the light is guided by the core; creating a long period optical grating in the optical fiber by stressing the fiber such that a plurality of localized changes in an index of refraction in the first core are created, the optical grating causing at least some of the light guided by the first core to be coupled to a mode not guided by a fundamental mode of the first core; determining a wavelength at which is coupled to a mode not guided by the fundamental mode of the first core; calculating a temperature based at least in part on the wavelength; measuring an amount of light coupled to a mode not guided by the first core; and calculating a pressure based on the amount of light coupled to a mode not guided by the fundamental mode of the first core.