Distance measurement using incoherent optical reflectometry

US8681322B2 · kind B2 · utility

Assignee

• Baker Hughes Holdings LLC · US

Inventors

• Alexander M. Barry · Christiansburg, US
• Roger Glen Duncan · Christiansburg, US
• Brooks A. Childers · Christiansburg, US
• Robert M. Harman · Troutville, US
• Daniel S. Homa · Blacksburg, US
• Ajit Balagopal · Christiansburg, US
• Philip R. Couch · Honiton, GB

Key dates

• Filing date: Oct 12, 2011
• Grant date: Mar 25, 2014
• Expiry date: Jun 6, 2032

Classification

• Technology area (CPC G): Physics
• CPC primary: G01S17/88
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A method for estimating a distance includes: generating an optical signal having a wavelength that is within a wavelength range, the optical signal modulated via a modulation signal having a modulation frequency; transmitting the modulated optical signal from a light source into the optical fiber, the optical fiber in contact with a moveable strain inducing element located at the position along the optical fiber, the optical fiber including a plurality of sensing locations configured to reflect light within the wavelength range when under strain from the strain inducing element and transmit light within the wavelength range when not under strain from the strain inducing element; receiving a reflected signal including light reflected from at least one of the sensing locations; demodulating the reflected signal with a reference signal to generate reflected signal data; and determining the distance to the position along the optical fiber based on the reflected signal data.