Fiber optic delay line filter
US4128759A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 21, 1977 |
| Grant date | Dec 5, 1978 |
| Priority date | — |
| Expiry date | Nov 21, 1997 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B6/2861
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A fiber optic delay line filter receives light energy input signals repretative of any form of temporally varying signals such as electrical or acoustical, for example. A plurality of fiber optic light paths each having a determinably variant optical propagation delay, receives and transmits the light energy signals. A photo responsive means receives the delayed output light energy signals transmitted by the plurality of fiber optic light paths and produces a single electrical output signal as a function of the sum of the delayed output light energy signals, thus performing a filtering or correlation function. In a preferred embodiment, an injection laser or light emitting diode may be employed as the means for converting the temporally varying input signals to commensurate light energy signals. In a variant embodiment, a single fiber optic light path, having a partially reflective surface at each end, gives effect to multiple reflective transmissions along the length of the fiber optic light path which are then detected by a photo responsive device, providing a narrowband filter output as a function of the length and number of multiple reflective transmissions.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.