Fiber-optic transmission sensor with modulator
US5471546A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 13, 1994 |
| Grant date | Nov 28, 1995 |
| Priority date | — |
| Expiry date | Dec 13, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01D5/35351
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Fiber-optic sensors are used in reflection or transmission operation in almost all fields of measuring technology, inter alia for monitoring industrial installations, in medical diagnostics and in aerospace. In this context, the effects of mechanical, electrical, magnetic, acoustic, thermal and chemical signals are evaluated. In order to make possible a simpler signal evaluation, laser light from a light source is coupled into a feed line optical fiber parallel to one of its two principal axes. At a 1st splice point, the light is introduced into a 1st reference optical fiber, whose principal axes are rotated with respect to those of the feed line optical fiber by 45.degree.. At a 2nd splice point, the light reaches a 2nd reference optical fiber of the same length as the 1st reference optical fiber and with its principal axes rotated with reference to the 1st reference optical fiber by 90.degree.. At a 3rd splice point, the light is coupled into a low-birefringent optical fiber, which firstly forms a .lambda./4-fiber-optic loop and subsequently forms an optical sensor. By means of a phase modulator (M) in conjunction with the 1st reference optical fiber, the phase shift of the light…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.