Accession Number : ADD012121

Title :   Fiber Optic Interferometer Using Two Wavelengths or Variable Wavelength.

Descriptive Note : Patent,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Giallorenzi,Thomas G ; Sheem,Sang K ; Taylor,Henry F

Report Date : 12 Nov 1985

Pagination or Media Count : 12

Abstract : This patent discloses a fiber optic interferometric physical sensor. A fiber optical Mach-Zehnder interferometer includes a sensor arm and a reference arm having different optical path lengths. A transducer coupled to the sensor arm modulates the phase of light signals passing therethrough in response to a physical quantity. The interferometer is supplied with an input optical signal which includes light components at two different wavelengths. The detected intensity of the output of the interferometer includes two components, each of which vary in relation to the physical quantity. Each output component is related to one of the two optical input wavelengths. The two output components differ in phase by an amount proportional to the path length difference between the sensor and reference arms and proportional to the wavelength difference between the sensor and reference arms and proportional to the wavelength difference between the light components of the input optical signal. The phase difference is adjusted such that the sensitivities of the two output components to the physical quantity are never simultaneously at a minimum. In an alternative embodiment, a single laser having a continuously variable wavelength is used with the interferometer having differeing sensor and reference path lengths to achieve maximum sensitivity.

Descriptors :   *PATENTS, *INTERFEROMETERS, *FIBER OPTICS, OPTICAL DETECTORS, PHASE MODULATION, LIGHT MODULATORS, INPUT, OUTPUT, DUAL MODE

Subject Categories : Test Facilities, Equipment and Methods
      Fiber Optics and Integrated Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE