Optical switch employing first and second ferroelectric cells with alignment layers having alignment directions offset by 45.degree.
US5414541A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 1, 1993 |
| Grant date | May 9, 1995 |
| Priority date | — |
| Expiry date | Jun 1, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04Q2011/0035
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A liquid-crystal optical beam switch comprising: a first birefringent layer (14) which divides an input beam (24) into its two polarization components; a first segmented twisted nematic liquid-crystal polarization modulator (16), the segments (30,32) of which rotate one of the polarization beams by 90.degree. but not the other so they both have the same polarization state and which polarization state depends on the biasing state of a two-state biasing source (33); a second birefringent layer 18 which displaces the beams in a direction perpendicular to that produced by the first birefringent layer if they are of one polarization but do not displacement them if they are of the other polarization dependent upon the biasing state; a second segmented twisted nematic liquid-crystal polarization modulator (20) the segments (50,52) of which are oppositely biased from the segments of the first liquid-crystal modulator to thereby restore the original polarization difference; and a third birefringent layer (22) which, acting conversely to the first birefringent layer, recombines the beams into one of two output beams (58,64) dependent on the biasing state. A further stage of switching is prov…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.