Multimode communications systems and method using same
US6064786A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 6, 1997 |
| Grant date | May 16, 2000 |
| Priority date | — |
| Expiry date | Nov 6, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B6/14
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for increasing the operational bandwidth of a multimode optical fiber communications system is provided. The method comprises launching optical radiation into the core of the multimode fiber away from the center of the core so as to strongly excite mid order modes of the multimode fiber, but to only weakly excite low order and high order modes of the multimode fiber. The mid order modes excited are predominately within a small number of mode groups and thus have similar propagation constants. This leads to a reduction in modal dispersion and thus to a significant increase in bandwidth compared to an overfilled launch. The offset launch of the invention is tolerant both to the launch conditions and to any imperfections in the fiber refractive index profile. Modal noise performance is also enhanced. Embodiments of the invention employ a singlemode fiber, a multimode fiber or a lens to illuminate an end face of a multimode fiber with a small spot offset from the optical axis of the fiber.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.