US4063084A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dual channel optical homodyne receiver
Assignee: Raytheon Co
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Filing: 1976-07-19
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Granted: 1977-12-13
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Expires: 1996-07-19
Abstract
Abstract An improved homodyne receiver for use in wideband optical communications systems is disclosed. The receiver utilizes quadrature demodulation of the optical signal in the manner of a two-phase receiver. A beam-splitting/phase-splitting optical assembly is used to channelize the received and the local oscillator beams to a pair of optical detectors. Squaring amplifiers in the quadrature channels followed by a summing network provide an output signal which is proportional to the square of the modulation of the input signal. This receiver is especially well-suited to the reception of Pulse Code Modulated optical signals.
Inventors
- 👤 Frank E. Goodwin
- 👤 Thomas A. Nussmeier
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 21:54
CPC Classifications
H; H04; H04B; H04B10/00; H04B10/60; H04B10/61; H04B10/614; H04B10/63
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
270 words
An optical homodyne receiver comprising, in combination: optical input means for receiving an input signal, said input signal being characterized by a carrier frequency and information-containing modulation components; a laser oscillator for generating a local oscillator signal having substantially the same frequency as said carrier frequency; an optical assembly coupled to said optical input means and to said laser oscillator, said optical assembly being capable of combining a first portion of said input signal with a first portion of said local oscillator signal and a second portion of said input signal with a second portion of said local oscillator signal, the phase difference between the first portion of said local oscillator signal and the carrier of the first portion of said input signal differing by substantially 90 degrees from the phase difference between the second portion of said local oscillator signal and the carrier of the second portion of said input signal; a first optical detector coupled to said optical assembly for detecting the first portion of said input signal with respect to the first portion of said local oscillator signal to produce a first video signal; a second optical detector coupled to said optical assembly for detecting the second portion of said input signal with respect to the second portion of said local oscillator signal to produce a second video signal; means coupled to said first optical detector for squaring said first video signal; means coupled to said second optical detector for squaring said second video signal; summing means for combining said first and second squared video signals; and means for deriving an output signal from said summing means.
Claim 2
Dependent Claim
270 words
An optical homodyne receiver comprising, in combination: optical input means for receiving an input signal, said input signal being characterized by a carrier frequency and information-containing modulation components; a laser oscillator for generating a local oscillator signal having substantially the same frequency as said carrier frequency; an optical assembly coupled to said optical input means and to said laser oscillator, said optical assembly being capable of combining a first portion of said input signal with a first portion of said local oscillator signal and a second portion of said input signal with a second portion of said local oscillator signal, the phase difference between the first portion of said local oscillator signal and the carrier of the first portion of said input signal differing by substantially 90 degrees from the phase difference between the second portion of said local oscillator signal and the carrier of the second portion of said input signal; a first optical detector coupled to said optical assembly for detecting the first portion of said input signal with respect to the first portion of said local oscillator signal to produce a first video signal; a second optical detector coupled to said optical assembly for detecting the second portion of said input signal with respect to the second portion of said local oscillator signal to produce a second video signal; means coupled to said first optical detector for squaring said first video signal; means coupled to said second optical detector for squaring said second video signal; summing means for combining said first and second squared video signals; and means for deriving an output signal from said summing means.
Claim 3
Dependent Claim
16 words
The receiver according to claim 1 wherein said first and second squaring means comprise squaring amplifiers.
Claim 4
Dependent Claim
27 words
The receiver according to claim 1 wherein said first portion of said input signal is substantially equal in magnitude to said second portion of said input signal.
Claim 5
Dependent Claim
18 words
The receiver according to claim 1 wherein said means for deriving an output signal comprises a level detector.
Claim 6
Dependent Claim
45 words
The receiver according to claim 1 wherein said optical assembly comprises, in combination: a first optical quarter-wave plate; a second optical quarter-wave plate; an optical beam combiner coupled to said first and second quarter-wave plates; and a polarization beam splitter coupled to said beam combiner.
Claim 7
Dependent Claim
25 words
The receiver according to claim 5 wherein said first optical quarter-wave plate is adapted for rotation about an axis substantially parallel to its optical axis.
Claim 8
Dependent Claim
141 words
An optical homodyne receiver comprising, in combination: first and second optical detectors each having an optical input and a video output; an optical input signal; a laser oscillator for generating a local oscillator signal; an optical assembly coupling said local oscillator signal and said input signal to said first and second optical detectors in adjustable proportions, the portions of said local oscillator signals coupled to said first and second optical detectors differing by substantially 90° with respect to the carrier of said input signal at the optical inputs of said first and second optical detectors; a summing network having at least two inputs and an output; first and second signal squaring means for coupling the outputs of said optical detectors to the inputs of said summing network; and means for deriving an output signal from the output of said summing network.
Claim 9
Dependent Claim
141 words
An optical homodyne receiver comprising, in combination: first and second optical detectors each having an optical input and a video output; an optical input signal; a laser oscillator for generating a local oscillator signal; an optical assembly coupling said local oscillator signal and said input signal to said first and second optical detectors in adjustable proportions, the portions of said local oscillator signals coupled to said first and second optical detectors differing by substantially 90° with respect to the carrier of said input signal at the optical inputs of said first and second optical detectors; a summing network having at least two inputs and an output; first and second signal squaring means for coupling the outputs of said optical detectors to the inputs of said summing network; and means for deriving an output signal from the output of said summing network.
Claim 10
Dependent Claim
16 words
The receiver according to claim 7 wherein said first and second squaring means comprise squaring amplifiers.
Claim 11
Dependent Claim
18 words
The receiver according to claim 7 wherein said means for deriving an output signal comprises a level detector.
Claim 12
Dependent Claim
45 words
The receiver according to claim 7 wherein said optical assembly comprises in combination: a first optical quarter-wave plate; a second optical quarter-wave plate; an optical beam combiner coupled to said first and second quarter-wave plates; and a polarization beam splitter coupled to said beam combiner.
Claim 13
Dependent Claim
25 words
The receiver according to claim 10 wherein said first optical quarter-wave plate is adapted for rotation about an axis substantially parallel to its optical axis.
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) | 1980-12-12 | 1981-06-13 | 1981-12-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-12-12 | 1985-06-13 | 1985-12-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-12-12 | 1989-06-13 | 1989-12-13 | $7700.00 | Window Closed / Lapsed |