EP0428151A2
Expired / Lapsed
EP
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Distortion canceling fiber optic transmission system
Assignee: Arris Technology Inc
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Filing: 1990-11-14
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Granted: —
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Expires: 2010-11-14
Abstract
Abstract A fiber optic communication system provides parallel paths (30,32) to enable cancelation of even order harmonic distortion components. A pair of parallel optical fibers (30,32) is provided. Each of the fibers is coupled to a corresponding transmitter (26,28) at one end of the pair and to a corresponding receiver (34,36) at the other end of the pair. The transmitters are modulated with an input signal applied to the transmitters at a 180° phase differential. The 180° phase shifted signals are combined (50) at the receivers to recover the input signal while canceling even order distortion products introduced by the transmitters. A method is provided for balancing the system upon installation.
Inventors
- 👤 Michael F. Jeffers
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-03 16:58
CPC Classifications
H; H04; H04B; H04B10/00; H04B10/25; H04B10/2507; H04B10/03; H04B10/032
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
155 words
Apparatus for communicating signals over an optical fiber transmission path comprising: a first light source; means for coupling said first light source to a first optical fiber; means for modulating said first light source with an input signal; a second light source; means for coupling said second light source to a second optical fiber; means for shifting the phase of said input signal 180°; means for modulating said second light source with said 180° phase shifted input signal; means for receiving modulated light from said first light source at a remote end of said first fiber to provide a first output signal; means for receiving modulated light from said second light source at a remote end of said second fiber to provide a second output signal; and means for combining the first and second output signals to recover said input signal while canceling even order distortion products contained in the first and second output signals.
Claim 2
Dependent Claim
155 words
Apparatus for communicating signals over an optical fiber transmission path comprising: a first light source; means for coupling said first light source to a first optical fiber; means for modulating said first light source with an input signal; a second light source; means for coupling said second light source to a second optical fiber; means for shifting the phase of said input signal 180°; means for modulating said second light source with said 180° phase shifted input signal; means for receiving modulated light from said first light source at a remote end of said first fiber to provide a first output signal; means for receiving modulated light from said second light source at a remote end of said second fiber to provide a second output signal; and means for combining the first and second output signals to recover said input signal while canceling even order distortion products contained in the first and second output signals.
Claim 3
Dependent Claim
23 words
Apparatus in accordance with claim 1 wherein said first and second output signals are electrical signals, and said combining means comprise a transformer.
Claim 4
Dependent Claim
15 words
Apparatus in accordance with claim 2 wherein said input and output signals are RF signals.
Claim 5
Dependent Claim
20 words
Apparatus in accordance with one of the preceding claims wherein said first and second optical fibers are identical parallel fibers.
Claim 6
Dependent Claim
19 words
Apparatus in accordance with one of the preceding claims wherein said first and second light sources are matched lasers.
Claim 7
Dependent Claim
16 words
Apparatus in accordance with one of the preceding claims wherein said receiving means comprise matched photodetectors.
Claim 8
Dependent Claim
20 words
Apparatus in accordance with one of claims 4 to 6 wherein said fibers are bonded together within a single cable.
Claim 9
Dependent Claim
29 words
Apparatus in accordance with one of the preceding claims further comprising: means for adjusting the amplitude of one or both of said output signals to provide a desired balance.
Claim 10
Dependent Claim
29 words
Apparatus in accordance with one of the preceding claims further comprising: means for adjusting the phase of one or both of said output signals to provide a desired balance.
Claim 11
Dependent Claim
81 words
A fiber optic communication system comprising: a pair of parallel optical fibers, each coupled to a corresponding transmitter at one end of said pair and to a corresponding receiver at the other end of said pair; means for modulating said transmitters with an input signal applied to the transmitters at a 180° phase differential; and means for combining the 180° phase shifted signals at said receivers to recover said input signal while canceling even order distortion products introduced by said transmitters.
Claim 12
Dependent Claim
81 words
A fiber optic communication system comprising: a pair of parallel optical fibers, each coupled to a corresponding transmitter at one end of said pair and to a corresponding receiver at the other end of said pair; means for modulating said transmitters with an input signal applied to the transmitters at a 180° phase differential; and means for combining the 180° phase shifted signals at said receivers to recover said input signal while canceling even order distortion products introduced by said transmitters.
Claim 13
Dependent Claim
15 words
A communication system in accordance with claim 10 wherein said combining means comprises a transformer.
Claim 14
Dependent Claim
28 words
A communication system in accordance with claim 10 or 11 further comprising: means for balancing the amplitudes of the 180° phase shifted signals prior to said combining means.
Claim 15
Dependent Claim
31 words
A communication system in accordance with one of claims 10 to 12 further comprising: means for adjusting the phase differential between said 180° phase shifted signals prior to said combining means.
Claim 16
Independent Claim
91 words
A method for communicating signals over an optical fiber transmission path comprising the steps of: transmitting an input signal over a first fiber in a pair of optical fibers; transmitting said input signal over the second fiber in said pair 180° out of phase with respect to the transmission on said first fiber; receiving said 180° phase shifted signals at a remote end of said fiber pair; and combining the received, 180° phase shifted signals to recover said input signal while canceling even order distortion products introduced by said transmitting steps.
Claim 17
Independent Claim
91 words
A method for communicating signals over an optical fiber transmission path comprising the steps of: transmitting an input signal over a first fiber in a pair of optical fibers; transmitting said input signal over the second fiber in said pair 180° out of phase with respect to the transmission on said first fiber; receiving said 180° phase shifted signals at a remote end of said fiber pair; and combining the received, 180° phase shifted signals to recover said input signal while canceling even order distortion products introduced by said transmitting steps.
Claim 18
Dependent Claim
97 words
A method in accordance with claim 14 comprising the steps of: transmitting a test signal instead of an input signal over each of said first and second fibers, the test signal being in phase on both of said fibers; receiving said test signal on both fibers at said remote end of the fiber pair; combining the test signal received from said first fiber with the test signal received from said second fiber; monitoring the combined signal to determine its amplitude; and adjusting a parameter at the remote end of said fiber pair to null the combined signal.
Claim 19
Dependent Claim
23 words
A method in accordance with claim 15 wherein said parameter is the level of the test signal received from one of said fibers.
Claim 20
Dependent Claim
24 words
A method in accordance with claim 16 wherein the effective length of one of said fibers is also adjusted to null the combined signal.
Claim 21
Dependent Claim
19 words
A method in accordance with claim 15 wherein said parameter is the effective length of one of said fibers.
References Cited (Backward Citations)
No citation records indexed.
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