Fiber optic acoustic sensor array based on Sagnac interferometer

US6097486A · kind A · utility

Assignee

• The Board of Trustees of the Leland Stanford Junior University · US

Inventors

• Benjamin J. Vakoc · Mountain View, US
• Michel J. F. Digonnet · Palo Alto, US
• Gordon S. Kino · Stanford, US
• H. John Shaw · Stanford, US

Key dates

• Filing date: Feb 19, 1999
• Grant date: Aug 1, 2000
• Expiry date: Feb 19, 2019

Classification

• Technology area (CPC G): Physics
• CPC primary: G01D5/35383
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A fiber optic acoustic sensor array is based upon a Sagnac interferometer rather than being based upon Mach-Zehnder interferometers as in known acoustic sensor arrays. The fiber optic acoustic sensor array is used to detect acoustic waves in water. By basing the sensor array on the Sagnac interferometer rather than on a Mach-Zehnder interferometer, the sensor array has a stable bias point, has reduced phase noise, has a larger dynamic range, and allows a broadband signal source to be used rather than requiring a more expensive narrowline laser. A large number of acoustic sensors can be multiplexed into the architecture of the Sagnac interferometer.