Optical fiber sensor
US9273948B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Nov 19, 2012 |
| Grant date | Mar 1, 2016 |
| Priority date | — |
| Expiry date | Jan 11, 2033 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01D5/35335
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An input of an optical interferometer is a periodical optical pulse. A phase of a first half and a latter half of a reference pulse is a 90 degree (independently orthogonal) phase difference. Two interferometric outputs i1 and i2, where the phase difference is 90 degrees from each other, are obtained by interference of the reference pulse and the signal pulse. θ is calculated by referring the amplitude of reference pulse and the signal pulse to remove the light intensity fluctuations. Two values of cos θ1 and cos θ2 are calculated and positions are determined on the cosine curve by obtaining θ1 and θ2 values. Δθ1 and Δθ2, which are the phase increment or decrement of both θ1 and θ2 in a T period, are summed and becomes the sensor output signal that removes the measurement range limitation of ±90 degrees (a half wavelength of light) of the light phase.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.