Optical mode filter employing radially asymmetric fiber
US9917410B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 28, 2016 |
| Grant date | Mar 13, 2018 |
| Priority date | — |
| Expiry date | Nov 28, 2036 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01S3/1618
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Fiber amplifier and/or mode filter including a linearly birefringent LMA fiber coiled at a radius of curvature over a bend length to differentiate a fundamental optical mode from supported higher-order modes through bending losses. The LMA fiber may be a polarization-maintaining (PM) fiber having a variety of geometrical core shapes and cladding configurations. In some embodiments, the birefringent LMA fiber includes a radially asymmetric core that is angularly rotated over a length of the coiled fiber to ensure bending losses are experienced in orthogonally oriented higher-order modes associated with some orientation relative to the core orientation. In some embodiments, the fiber coiling is two-dimensional with bending occurring only about one axis. In some embodiments, an asymmetric core is pre-spun to a predetermined axial spin profile. In some embodiments, angular rotation of the core is achieved through mechanically twisting an un-spun fiber over a length of the coil.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.