Birefringent fiber narrowband polarization coupler and method of coupling using same
US4801189A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 22, 1988 |
| Grant date | Jan 31, 1989 |
| Priority date | — |
| Expiry date | Feb 22, 2008 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S359/90
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
There is disclosed herein a fiber optic directional coupler for coupling light between two polarization modes. A highly birefringent fiber optic waveguide is positioned on a flat polished surface with either of the principal axes of birefringence oriented at an angle, preferably 45.degree., to the vertical. A ridged block is then pressed down on the fiber. The ridges of the block have longitudinal axes transverse to the longitudinal axis of the fiber. The width of the ridge faces is one-half beat length, and the spacing between the ridges in also one-half beat length. The stressed regions caused by the ridges cause coupling of light traveling in one polarization mode into the other polarization mode by abrupt shifting of the axes of birefringence at the boundaries of the stressed regions.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.