Patent US4873690A successfully refreshed from Google Patents.
US4873690A
Expired / Lapsed
US
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Optical switch
Assignee: British Telecommunications PLC
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Filing: 1987-12-14
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Granted: 1989-10-10
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Expires: 2007-12-14
Abstract
Abstract Using a semi-conductor laser amplifier 1 in reflection, an optical switch is achieved which can be applied as either an AND/OR, or a NAND/NOR, logic gate. The amplifier 1 responds to an optical input switching signal and the logical characteristics of its response can be controlled by selection of the drive current to the amplifier 1. The switch finds application in optical logic or communication systems.
Inventors
- 👤 Michael J. Adams
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 20:15
CPC Classifications
G; G02; G02F; G02F3/00
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
107 words
An optical switch comprising: a semi-conductor or optical amplifier having optical input and output ports located at a common end of an amplifier cavity, means for coupling a detuned optical input switching signal to the amplifier, and means for applying a driving electrical current to the amplifier, which driving current is selected to have either one of at least two different values, at a first value of which driving current the optical amplifier is operated as an AND/OR logic gate for input optical signals and at a second value of which driving current the optical amplifier is operated as a NAND/NOR logic gate for input optical signals.
Claim 2
Dependent Claim
107 words
An optical switch comprising: a semi-conductor or optical amplifier having optical input and output ports located at a common end of an amplifier cavity, means for coupling a detuned optical input switching signal to the amplifier, and means for applying a driving electrical current to the amplifier, which driving current is selected to have either one of at least two different values, at a first value of which driving current the optical amplifier is operated as an AND/OR logic gate for input optical signals and at a second value of which driving current the optical amplifier is operated as a NAND/NOR logic gate for input optical signals.
Claim 3
Dependent Claim
26 words
An optical switch according to claim 1 wherein the amplifier comprises a laser and the driving current lies below the lasing threshold current of that laser.
Claim 4
Dependent Claim
29 words
An optical switch according to claim 2 wherein the amplifier comprises a passive Fabry-Perot cavity laser and the switching signal is detuned from a cavity resonance of the laser.
Claim 5
Dependent Claim
64 words
An optical switch according to claim 2 wherein the amplifier comprises a laser having optical feedback strutures distributed along an optical lasing cavity and the switching signal is detuned from an output peak on the short wavelength side of a stop band of the laser, said stop band being a range of optical wavelengths which, when input to said amplifier, are substantially reflected therefrom.
Claim 6
Dependent Claim
30 words
An optical switch as in any of the preceding claim wherein an end facet of the amplifier cavity opposite said input and output ports is coated with a high-reflectivity coating.
Claim 7
Dependent Claim
21 words
An optical time-division switch comprising an optical switch according to any one of the preceding claims 1, 2, 3, or 4.
Claim 8
Dependent Claim
21 words
An optical signal regenerator comprising an optical switch according to any one of the preceding claims 1, 2, 3, or 4.
Claim 9
Dependent Claim
152 words
An optical switching method utilizing an optical switch providing AND/OR logical operations on input optical signals in a first condition and providing NAND/NOR logical operations on input optical signals in a second condition, said method comprising: providing a semi-conductor optical signal amplifier having an amplifying cavity with a common facet providing both an optical signal input port and an optical signal output port; inputting optical logic level signals to said input port; establishing an electrical driving current of a first magnitude through said semi-conductor optical signal amplifier to establish said first condition wherein AND/OR logic operations are performed on said input optical signals to provide output optical signals from said facet; and alternatively establishing an electrical driving current of a second magnitude through said semi-conductor optical signal amplifier to establish said second condition wherein NAND/NOR logic operations are performed on said input optical signals to provide output optical signals from said facet.
Claim 10
Dependent Claim
152 words
An optical switching method utilizing an optical switch providing AND/OR logical operations on input optical signals in a first condition and providing NAND/NOR logical operations on input optical signals in a second condition, said method comprising: providing a semi-conductor optical signal amplifier having an amplifying cavity with a common facet providing both an optical signal input port and an optical signal output port; inputting optical logic level signals to said input port; establishing an electrical driving current of a first magnitude through said semi-conductor optical signal amplifier to establish said first condition wherein AND/OR logic operations are performed on said input optical signals to provide output optical signals from said facet; and alternatively establishing an electrical driving current of a second magnitude through said semi-conductor optical signal amplifier to establish said second condition wherein NAND/NOR logic operations are performed on said input optical signals to provide output optical signals from said facet.
Claim 11
Dependent Claim
114 words
An optical signal logic switch capable of accepting plural combined logic level optical signals at an optical input port and of providing a corresponding AND/OR or NAND/NOR Boaleon logic optical resultant signal at an optical output, said switch comprising: a semi-conductor optical amplifier having an electrical drive bias current path therethrough and also having an optical amplifying cavity with common facet which acts both as an optical signal input port and an optical signal output port; and bias current control means connected to establish a predetermined electrical bias current through said path which bias current magnitude determines whether an optical output signal represents logical AND/OR or logical NAND/NOR operations upon the optical input signals.
Claim 12
Dependent Claim
114 words
An optical signal logic switch capable of accepting plural combined logic level optical signals at an optical input port and of providing a corresponding AND/OR or NAND/NOR Boaleon logic optical resultant signal at an optical output, said switch comprising: a semi-conductor optical amplifier having an electrical drive bias current path therethrough and also having an optical amplifying cavity with common facet which acts both as an optical signal input port and an optical signal output port; and bias current control means connected to establish a predetermined electrical bias current through said path which bias current magnitude determines whether an optical output signal represents logical AND/OR or logical NAND/NOR operations upon the optical input signals.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-10-09 | 1993-04-10 | 1993-10-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-10-09 | 1997-04-10 | 1997-10-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-10-09 | 2001-04-10 | 2001-10-10 | $7700.00 | Window Closed / Lapsed |