Dual liquid-crystal wavelength-selective optical switch
US6327019A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Feb 3, 1998 |
| Grant date | Dec 4, 2001 |
| Priority date | — |
| Expiry date | Feb 3, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04Q2011/0092
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A liquid-crystal switching element relying upon a segmented liquid-crystal polarization modulator, at least one frequency-dispersive grating and one or more polarization-dispersive elements, such as Wollaston prisms, to switch separate wavelength-divided signals among four optical paths. The switching is done complementally between the fibers of each pair, and the same switching is done for the two pairs. According to the invention, all four beams can be processed by a single set of serial optics. The invention is particularly useful as an optical interconnect between two optical fiber communications rings in which each ring includes two counter-rotating fibers. The invention advantageously uses a dielectric thin-film beam splitter for one of the polarization-dispersive elements and a Wollaston prism for the other. The reflective embodiment in which a mirror replaces all the components on the output side can be improved by using two semitransparent electrode layers on the input side separated by a quarter-wavelength of dielectric.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.