Acousto-optic fiber-optic frequency shifter using periodic contact with a surface acoustic wave
US4872738A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 18, 1986 |
| Grant date | Oct 10, 1989 |
| Priority date | — |
| Expiry date | Feb 18, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F1/0134
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An acoustic wave is propagated colinearly with the optical signals in an optical fiber to cause coupling of an optical signal in one propagation mode of the optical fiber to the other propagation mode in the optical fiber. The acoustic wave is selected to have an acoustic wave length which is shorter in the direction of optical propagation than the optical beat length between the two propagation modes of the fiber. In order to cause phase-matching between the two optical propagation modes, a periodic structure is used to cause the acoustic wave to contact the optical fiber at periodic locations so that the coupling between the two propagation modes is periodically enabled and disabled. The periodic contact of the acoustic wave with the optical fiber has the effect of adding a spatial propagation constant. The periodicity of the periodic structure is selected so that the spatial propagation constant of the periodic structure is equal to the mismatch in the propagation constants of the two optical propagation modes and the acoustic wave. The present invention thereby provides a means of obtaining greater shifts in the optical frequency while using a colinearly propagating acoustic wa…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.