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US5084779A
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Transmitter and transceiver for a coherent optical system
Assignee: British Telecommunications PLC
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Filing: 1988-04-14
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Granted: 1992-01-28
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Expires: 2008-04-14
Abstract
Abstract In a coherent optical system, a transmitter or transceiver having an optical source which feeds a single coherent wave to both a modulator and a bi-direction amplifier. The modulator generates a modulated information signal and the amplifier generates an unmodulated, amplified reference signal. A coupling means combines the modulated and amplified signals for transmission to a remote detector. The detector uses the amplified signal as the reference optical signal in a homodyne or heterodyne system.
Inventors
- 👤 Ian W. Stanley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 16:55
CPC Classifications
H; H04; H04B; H04B10/00; H04B10/29; H04B10/291; H04B10/297; H04B10/40; H04B10/60; H04B10/61; H04B10/63; H04B10/64
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
73 words
An optical transmitter for use in a coherent optical system comprising a single optical source coupled to a modulating means for generating a modulated information signal and to an optical amplifier to provide an amplified, unmodulated reference signal, a coupling means for combining said modulated information signal and said amplified, unmodulated reference signal; and a wavelength shifting means for shifting the wavelength of said source signal before modulation thereof by said modulating means.
Claim 2
Dependent Claim
73 words
An optical transmitter for use in a coherent optical system comprising a single optical source coupled to a modulating means for generating a modulated information signal and to an optical amplifier to provide an amplified, unmodulated reference signal, a coupling means for combining said modulated information signal and said amplified, unmodulated reference signal; and a wavelength shifting means for shifting the wavelength of said source signal before modulation thereof by said modulating means.
Claim 3
Dependent Claim
21 words
An optical transmitter according to claim 1 wherein said optical source comprises a laser and means for tuning said source signal.
Claim 4
Dependent Claim
113 words
An optical transceiver for use in a coherent optical system comprising a single optical source coupled to a modulating means providing a transmitted modulated information signal and to an optical amplifier providing a transmitted amplified, unmodulated reference signal; said optical amplifier providing bi-directional optical amplification in one direction for said transmitted reference signal and in the other direction both for a received modulated information signal and a received unmodulated reference signal; a coupling means for combining said transmitted information signal and said transmitted reference signal; and a receiver including a coherent detection receiver coupled to said amplifier for receiving an amplified input signal comprising said received information signal and said received reference signal.
Claim 5
Dependent Claim
113 words
An optical transceiver for use in a coherent optical system comprising a single optical source coupled to a modulating means providing a transmitted modulated information signal and to an optical amplifier providing a transmitted amplified, unmodulated reference signal; said optical amplifier providing bi-directional optical amplification in one direction for said transmitted reference signal and in the other direction both for a received modulated information signal and a received unmodulated reference signal; a coupling means for combining said transmitted information signal and said transmitted reference signal; and a receiver including a coherent detection receiver coupled to said amplifier for receiving an amplified input signal comprising said received information signal and said received reference signal.
Claim 6
Dependent Claim
43 words
An optical transceiver according to claim 3 wherein said coupling means comprises a directional coupler and an optical isolator located between said optical source and said directional coupler so as to prevent any of the source signal coupling back into said optical source.
Claim 7
Dependent Claim
45 words
An optical transceiver according to claim 3 further comprising a second coupling means having a second directional coupler and a second optical isolator located between said second directional coupler and said modulating means so as to prevent said input signal coupling into said modulating means.
Claim 8
Dependent Claim
24 words
An optical transceiver according to claim 3 wherein said receiver includes a filter means for selecting said input signal from a plurality of signals.
Claim 9
Dependent Claim
31 words
An optical transceiver as in claim 3 further comprising a wavelength shifting means for shifting the wavelength of the signal from said optical source before modulation thereof by said modulating means.
Claim 10
Dependent Claim
86 words
A coherent optical system having a transceiver; said transceiver having an output means for transmitting optical signals having a modulated information component and an amplified, unmodulated reference component, said components being formed from a single input source means of coherent light, said transceiver also including means for receiving optical signals having reference and information components; said transceiver further comprising a bidirectional amplifier for generating said amplified unmodulated reference component of the signals to be transmitted and for amplifying said reference and information components of received signals.
Claim 11
Dependent Claim
86 words
A coherent optical system having a transceiver; said transceiver having an output means for transmitting optical signals having a modulated information component and an amplified, unmodulated reference component, said components being formed from a single input source means of coherent light, said transceiver also including means for receiving optical signals having reference and information components; said transceiver further comprising a bidirectional amplifier for generating said amplified unmodulated reference component of the signals to be transmitted and for amplifying said reference and information components of received signals.
References Cited (Backward Citations)
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JPS54114005A
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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) | 1995-01-27 | 1995-07-29 | 1996-01-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-01-27 | 1999-07-29 | 2000-01-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-01-27 | 2003-07-29 | 2004-01-28 | $7700.00 | Window Closed / Lapsed |