Patent US4969717A successfully refreshed from Google Patents.
US4969717A
Expired / Lapsed
US
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Optical switch
Assignee: British Telecommunications PLC
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Filing: 1988-06-03
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Granted: 1990-11-13
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Expires: 2008-06-03
Abstract
Abstract An optical switch includes a series of 2(n-1) macro-cells each having a variable polarization rotating cell and a birefringent cell. Each rotating cell is divided into individually addressable and switchable sub-cells. Some of the macro-cells have birefringent cells having a first orientation. In these macro-cells, sub-cells switch light passing through position Pi to either position Pi or Pi+1 of the rotating cell of the next macro-cell in the series. Other macro-cells have birefringent cells having a second orientation. In these macro-cells, the sub-cells switch light passing through position Pi to either position Pi or Pi-1 of the rotating cell of the next macro-cell in the series. The sub-cells of the macro-cells are positioned such that light from any one of several inputs is switchable independently to any one of several outputs.
Inventors
- 👤 Stephen R. Mallinson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 15:23
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/29; G02F1/31
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
165 words
An optical switch comprising: a series of 2(n-1) macro-cells each having a variable polarization rotating cell with up to n individually addressable sub-cells, each of said sub-cells being located at one of n positions Pl to Pn, and a birefringent cell adjacent said rotating cell; (n-1) of said birefringent cells being in a first orientation so that light passing through an addressable sub-cell position Pi is switchable to pass through either of sub-cell positions Pi or Pi+l of said rotating cell of the next macro-cell in said series, and (n-1) birefringent cells being in a second orientation so that light passing through an addressable sub-cell position Pi is switchable to pass through either of sub-cell positions Pi or Pi-l of said rotating cell of the next macro-cell in said series, said sub-cells being positioned to provide that light from any one of m inputs is switchable independently to any of m outputs, where m is less than or equal to n and greater than 1.
Claim 2
Dependent Claim
165 words
An optical switch comprising: a series of 2(n-1) macro-cells each having a variable polarization rotating cell with up to n individually addressable sub-cells, each of said sub-cells being located at one of n positions Pl to Pn, and a birefringent cell adjacent said rotating cell; (n-1) of said birefringent cells being in a first orientation so that light passing through an addressable sub-cell position Pi is switchable to pass through either of sub-cell positions Pi or Pi+l of said rotating cell of the next macro-cell in said series, and (n-1) birefringent cells being in a second orientation so that light passing through an addressable sub-cell position Pi is switchable to pass through either of sub-cell positions Pi or Pi-l of said rotating cell of the next macro-cell in said series, said sub-cells being positioned to provide that light from any one of m inputs is switchable independently to any of m outputs, where m is less than or equal to n and greater than 1.
Claim 3
Dependent Claim
19 words
An optical switch as claimed in claim 1 in which said variable polarization rotating sub-cells are liquid crystal cells.
Claim 4
Dependent Claim
19 words
An optical switch as claimed in claim 2 in which said liquid crystal is a smectic c liquid crystal.
Claim 5
Dependent Claim
21 words
A optical switch as claimed in any one of claims 1 through 3 in which said birefringent cells are calcite crystals.
Claim 6
Dependent Claim
23 words
An optical switch as claimed in any one of claims 1, 2, or 3 in which said birefringent cells comprise stressed polymer sheets.
Claim 7
Dependent Claim
26 words
An optical switch as claimed in any one of claims 1, 2 or 3 which macro-cells having birefringent cells of the same orientation are grouped together.
Claim 8
Dependent Claim
38 words
An optical switch as claimed in any one of claims 1, 2 or 3 in which said macro-cells are grouped in pairs of macro-cells, each of said pairs including said first orientation and said second orientation birefringent cells.
Claim 9
Dependent Claim
166 words
An optical switch having a series of macro-cells, each said macro-cell comprising: a variable polarization rotating cell divided into sub-cells, each of said sub-cells being located at one of n positions P1 to Pn; a birefringent cell adjacent to said rotating cell; said birefringent cell in each of a first portion of said macro-cells having a first orientation, said sub-cells being switchable so that light entering sub-cell position Pi in one of said first portion macro-cells passes through to either sub-cell position Pi or Pi+1 in the next macro-cell in said series; said birefringent cell in each of a second portion of said macro-cells having a second orientation, said sub-cells being switchable so that light entering sub-cell position Pi in one of said second portion macro-cells passes through to either sub-cell position Pi or Pi-1 in the next macro-cell in said series, and said sub-cells being positioned to direct light from any one of a plurality of inputs to any one of a plurality of outputs.
Claim 10
Dependent Claim
166 words
An optical switch having a series of macro-cells, each said macro-cell comprising: a variable polarization rotating cell divided into sub-cells, each of said sub-cells being located at one of n positions P1 to Pn; a birefringent cell adjacent to said rotating cell; said birefringent cell in each of a first portion of said macro-cells having a first orientation, said sub-cells being switchable so that light entering sub-cell position Pi in one of said first portion macro-cells passes through to either sub-cell position Pi or Pi+1 in the next macro-cell in said series; said birefringent cell in each of a second portion of said macro-cells having a second orientation, said sub-cells being switchable so that light entering sub-cell position Pi in one of said second portion macro-cells passes through to either sub-cell position Pi or Pi-1 in the next macro-cell in said series, and said sub-cells being positioned to direct light from any one of a plurality of inputs to any one of a plurality of outputs.
Claim 11
Dependent Claim
34 words
An optical switch as in claim 8 having 2(n-1) of said macro-cells, and in which the number said first portion of macro-cells is (n-1), and the number of said second portion macro-cells is (n-1).
Claim 12
Dependent Claim
129 words
An optical switch comprising: a series of macro-cells each having a variable polarization rotating cell with up to n individually addressable sub-cells and a birefringent cell adjacent to said rotating cell; each of said sub-cells located at one of n positions P1 to Pn, said sub-cells being switchable so that light entering sub-cell position Pi in one of said macro-cells passes through to either sub-cell position Pi or Pi+1 in the next macro-cell in said series; a mirror adjacent to the last macro-cell in said series, said mirror reflecting light exiting said last macro-cell, and said sub-cells being positioned to direct light from any one of m inputs back to any one of said m inputs, where m is less than or equal to n and greater than one.
Claim 13
Dependent Claim
129 words
An optical switch comprising: a series of macro-cells each having a variable polarization rotating cell with up to n individually addressable sub-cells and a birefringent cell adjacent to said rotating cell; each of said sub-cells located at one of n positions P1 to Pn, said sub-cells being switchable so that light entering sub-cell position Pi in one of said macro-cells passes through to either sub-cell position Pi or Pi+1 in the next macro-cell in said series; a mirror adjacent to the last macro-cell in said series, said mirror reflecting light exiting said last macro-cell, and said sub-cells being positioned to direct light from any one of m inputs back to any one of said m inputs, where m is less than or equal to n and greater than one.
Claim 14
Dependent Claim
16 words
An optical switch as in claim 10 in which said rotating sub-cells comprise liquid crystal cells.
Claim 15
Dependent Claim
18 words
An optical switch as in claim 11 in which said liquid crystal cells comprise smectic c liquid crystals.
Claim 16
Dependent Claim
18 words
An optical switch as in any one of claims 10-12 in which said birefringent cells comprise calcite crystals.
Claim 17
Dependent Claim
18 words
An optical switch as in any of claims 10-12 in which said birefringent cells comprise stressed polymer sheets.
Claim 18
Dependent Claim
100 words
An optical switch including a series of cascaded macro-cell switches, each said macro-cell switch comprising: a birefringent cell; and an plurality of individually controllable polarization rotating sub-cells located adjacent said birefringent cell at corresponding n optical input/output port positions P1 to Pn; said birefringent cell having predetermined orientation and dimensions to cause optical signals from a given input port position Pi to pass (a) to the same output port position Pi or (b) to a next adjacent output port position (Pi+1 or Pi-1) depending upon the state of the corresponding polarization rotating cell and the orientation of said birefringent cell.
Claim 19
Dependent Claim
100 words
An optical switch including a series of cascaded macro-cell switches, each said macro-cell switch comprising: a birefringent cell; and an plurality of individually controllable polarization rotating sub-cells located adjacent said birefringent cell at corresponding n optical input/output port positions P1 to Pn; said birefringent cell having predetermined orientation and dimensions to cause optical signals from a given input port position Pi to pass (a) to the same output port position Pi or (b) to a next adjacent output port position (Pi+1 or Pi-1) depending upon the state of the corresponding polarization rotating cell and the orientation of said birefringent cell.
Claim 20
Dependent Claim
37 words
An optical switch as in claim 15 having 2(n-1) macro-cell switches and having n of said polarization rotating sub-cells disposed in a linear array adjacent an input face of the birefringent cell for each said macro-cell switch.
Claim 21
Dependent Claim
96 words
An optical switch as in claim 15 having 2(n-1) macro-cell switches and having (n-1) of said macro-cell switches with birefringent cells of a first orientation and having (n-1) of said macro-cell switches with birefringent cells of a second orientation, macro cells having said first orientation directing optical signals input at Pi to output position Pi+1 depending upon the state of the ith polarization rotating sub-cell for that macro-cell; macro-cells having said second orientation directing optical signals input at Pi to output position Pi-1 depending upon the state of the ith polarization rotating sub-cell for that macro-cell.
Claim 22
Dependent Claim
34 words
An optical switch as in claim 15 further comprising: a reflective surface disposed at the output of said series of cascaded macro-cell switches so as to redirect output optical signals back through the macro-cells.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-11-12 | 1994-05-14 | 1994-11-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-11-12 | 1998-05-14 | 1998-11-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-11-12 | 2002-05-14 | 2002-11-13 | $7700.00 | Window Closed / Lapsed |