Reduction of modal and chromatic material dispersion in a multimode optical fiber
US4067642A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 3, 1976 |
| Grant date | Jan 10, 1978 |
| Priority date | — |
| Expiry date | Aug 3, 1996 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B10/2525
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Modal dispersion and chromatic material dispersion in a multimode optical fiber is reduced by feeding the rays of the light beam into the end of the optical fiber the angle of each ray relative to the axis of the fiber varied in accordance with the wavelength of the ray. The shortest ray is fed at a zero angle and the longest wavelength at angle of .phi. max. .phi. max. is defined by the equation ##EQU1## This invention relates to the reduction of both modal and chromatic material dispersion in a multimode optical fibre. Multimode guides are currently used in fibre-bundle optical communications and will also appear in the next generation of individual-fibre systems. Their 50 to 100.mu.m diameter cores are compatible with multimode LED sources and simple connecting and tapping techniques. Unfortunately, their information carrying capacity is limited by the variation of signal group velocity both with mode number and with light wavelength; this presents a serious limitation with large numerical aperture fibres and broadband sources. Prior art in this field has concentrated on gradient-index optical fibres to approximately equalize all ray paths and hence reduce mode dispersion. Howev…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.