Spatial filtering of higher order modes in multimode fibers
US8909017B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | May 30, 2012 |
| Grant date | Dec 9, 2014 |
| Priority date | — |
| Expiry date | Jan 2, 2033 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B10/2581
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A mode filter for eliminating the propagation of higher-order modes along a section of optical multimode fiber comprises a graded index (GRIN) lens, preferably of a quarter-pitch length, and a pinhole element in the form of a small core fiber. This configuration creates a Fourier spatial filter assembly that removes higher order modes propagating along an optical fiber while capturing the fundamental mode of the optical signal. A section of GRIN fiber is preferably used as the lens, with the small core fiber disposed at the output of the GRIN fiber lens to collect substantially only the on-axis fundamental mode of the optical signal. Since the higher order modes are shifted away from the origin by the GRIN fiber lens, only the fundamental mode signal is captured by the small core fiber.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.