Spatially-weighted two-mode optical fiber sensors

US5224182A · kind A · utility

Assignees

• Virginia Polytechnic Institute and State University · US
• VIRGINIA TECH INTELLECTUAL PROPERTIES, INC. · US
• Center for Innovative Technology · US

Inventors

• Kent A. Murphy · Roanoke, US
• Ashish Madhukar Vengsarkar · Berkeley Heights, US
• Michael Günther · Koblenzer Straße, DE
• Brian R. Fogg · Blacksburg, US
• Richard O. Claus · Blacksburg, US

Key dates

• Filing date: Aug 29, 1991
• Grant date: Jun 29, 1993
• Expiry date: Aug 29, 2011

Classification

• Technology area (CPC G): Physics
• CPC primary: G01D5/3538
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

Tapered two-mode optic fibers are used as sensors with sensitivity varying as a function of length. The optical fiber sensors act as vibrational-mode filters thereby performing initial signal processing of the sensor signal. The sensors are based on the differential propagation constant in a two-mode fiber that is directly dependent on the normalized frequency or V-number. Tapering the fiber changes the V-number and hence can change the sensitivity of the sensor along its length. By choosing an appropriate weighting function in the manufacture of the sensor, it is possible to implement vibrational-mode analysis, vibrational-mode filtering and other functions that are critical in control system applications.