Wavelength reference system for optical measurements

US7268884B2 · kind B2 · utility

Assignee

• OPTOPLAN AS · NO

Inventors

• Jon Thomas Kringlebotn · Trondheim, NO
• Hilde Nakstad · Trondheim, NO
• Dag Thingbo · Vikhammer, NO

Key dates

• Filing date: Dec 23, 2003
• Grant date: Sep 11, 2007
• Expiry date: Jan 24, 2025

Classification

• Technology area (CPC G): Physics
• CPC primary: G01J3/1895
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

Devices and methods of accurately determining optical wavelengths, such as the Bragg wavelengths of an FBG sensor array. Wavelength-swept light having a characteristic spectrum is swept over a bandwidth and is applied to an interference filter. The interference filter produces an optical spectrum having one or more reference peaks that are identifiable because of the characteristic spectrum. The optical spectrum is converted into electrical signals having at least one electrical signal that is identifiable because of the characteristic spectrum. The identifiable electrical signal is used by a signal processor as an absolute, high accuracy wavelength reference. Temperature compensation or temperature stabilization can compensate the characteristic wavelength. Fiber Bragg sensor systems can use the wavelength reference to determine the Bragg wavelength of FBG elements. The characteristic spectrum can be imparted by the light source or an optical element such as a transmission line filter.