Compact wavelength filter using optical birefringence and reflective elements
US6847786B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 4, 2000 |
| Grant date | Jan 25, 2005 |
| Priority date | — |
| Expiry date | Feb 4, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04Q2011/0035
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A wavelength division multiplexing/demultiplexing device is presented utilizing a polarization-based filter to separate odd and even wavelengths, or upper and lower channels of an input optical signal. The wavelength filter first converts the input signal to a predetermined polarization. A series of birefringent waveplates provide a polarization-dependent optical transmission function such that the polarized beam is decomposed into a first beam component carrying the first spectral band at a first polarization and a second beam component carrying the second spectral band at a second, orthogonal polarization. A beam displacer spatially separates the beam components into a pair of orthogonally-polarized beams. A quarter-wave plate converts these orthogonally-polarized beams into a pair of circularly-polarized beams, which are reflected by a mirror back along parallel optical paths through the quarter-wave plate, beam displacer, and waveplates. In the return pass, the quarter-wave plate converts the reflected circularly-polarized beams into two orthogonally-polarized beams having polarizations that are rotated by 90 degrees from those in the forward pass. The waveplates further purify…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.