Date of this Version
United States Patent, Patent No.: US 9,677,949 B1.
An in-line fiber-optic temperature sensor is disclosed. In an implementation, the in-line fiber-optic temperature sensor includes an optically transmissive fiber, a reflector, a microstructured fiber defining a channel therein for receiving a fluid, and a Fabry-Perot cavity in fluid communication with the micro structured fiber. The micro structured fiber can be retained between the optically transmissive fiber and the reflector. The Fabry-Perot cavity defined by a material and configured to receive a gas having an index of refraction that changes in a known way with temperature and pressure changes in fluid communication with the channel of the micro structured fiber. The in-line fiber-optic temperature sensor also includes a chamber defined between the optically transmissive fiber and the micro structured fiber for connecting in fluid communication with a vacuum/pressure source for changing pressure. The in-line fiber-optic temperature sensor also includes a sensor for determining an optical interferometric reflection spectrum associated with the Fabry-Perot cavity.