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US5293545A
Expired / Lapsed
US
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Optical source with reduced relative intensity noise
Assignee: Ciena Corp
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Filing: 1992-07-27
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Granted: 1994-03-08
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Expires: 2012-07-27
Abstract
Abstract Apparatus is provided for producing an optical carrier with low relative intensity noise. A portion of light output from a light source is sampled. An error signal representative of the relative intensity noise contained in the light output is generated. The error signal is subtracted from the light output from the light source to provide an optical carrier in which the relative intensity noise has been substantially reduced. The error signal can be subtracted using either an external optical intensity modulator or by converting the electrical signal to an optical signal and directly coupling it to the light output from the light source.
Inventors
- 👤 David R. Huber
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 10:37
CPC Classifications
H; H04; H04B; H04B10/00; H04B10/25; H04B10/2507
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
83 words
Apparatus for producing an optical carrier with low relative intensity noise comprising: a light source; means for sampling a portion of light output from said light source; means for generating an error signal from said sampled portion, said error signal being representative of relative intensity noise contained in the light from said light source; and means for subtracting said error signal from light output from said light source to provide an optical carrier in which the relative intensity noise has been substantially reduced.
Claim 2
Dependent Claim
83 words
Apparatus for producing an optical carrier with low relative intensity noise comprising: a light source; means for sampling a portion of light output from said light source; means for generating an error signal from said sampled portion, said error signal being representative of relative intensity noise contained in the light from said light source; and means for subtracting said error signal from light output from said light source to provide an optical carrier in which the relative intensity noise has been substantially reduced.
Claim 3
Dependent Claim
36 words
Apparatus in accordance with claim 1 wherein said subtracting means comprise a first external optical modulator coupled to modulate the light output from said light source and to receive said error signal as a modulating input.
Claim 4
Dependent Claim
27 words
Apparatus in accordance with claim 2 wherein said subtracting means further comprise an inverter for inverting said error signal prior to input to said external optical modulator.
Claim 5
Dependent Claim
46 words
Apparatus in accordance with claim 2 further comprising: a second external modulator coupled to receive said optical carrier from an output of said first external modulator; said second external modulator having a modulating input for receiving an information signal to be modulated onto said optical carrier.
Claim 6
Dependent Claim
29 words
Apparatus in accordance with claim 1 further comprising: means for adjusting the phase and amplitude of said error signal to minimize the relative intensity noise in said optical carrier.
Claim 7
Dependent Claim
53 words
Apparatus in accordance with claim 1 wherein said error signal is generated in the electrical domain, said apparatus further comprising: means for converting said sampled portion of light into an electrical signal; and means for converting said error signal to an optical signal for subtraction from the light output from said light source.
Claim 8
Dependent Claim
24 words
Apparatus in accordance with claim 1 further comprising an optical amplifier for amplifying the light from said light source prior to said sampling means.
Claim 9
Dependent Claim
59 words
Apparatus in accordance with claim 1 further comprising an optical amplifier coupled to an output of said light source, wherein: said sampling means sample a first portion of light prior to said optical amplifier and a second portion of light after said optical amplifier; and said error signal is generated from the difference between said first and second portions.
Claim 10
Dependent Claim
127 words
Apparatus for producing an optical carrier with low relative intensity noise comprising: a first light source for producing light at a first wavelength λ 1 ; means for sampling a portion of the light output from said first light source and providing an electrical error signal therefrom, said error signal being representative of relative intensity noise contained in the light from said first light source; a second light source for producing light at a second wavelength λ 2 and responsive to said error signal to provide an optical error signal equivalent to said electrical error signal; and means for combining said optical error signal with light output from said first light source to provide an optical carrier in which the relative intensity noise has been substantially reduced.
Claim 11
Dependent Claim
127 words
Apparatus for producing an optical carrier with low relative intensity noise comprising: a first light source for producing light at a first wavelength λ 1 ; means for sampling a portion of the light output from said first light source and providing an electrical error signal therefrom, said error signal being representative of relative intensity noise contained in the light from said first light source; a second light source for producing light at a second wavelength λ 2 and responsive to said error signal to provide an optical error signal equivalent to said electrical error signal; and means for combining said optical error signal with light output from said first light source to provide an optical carrier in which the relative intensity noise has been substantially reduced.
Claim 12
Dependent Claim
49 words
Apparatus in accordance with claim 9 wherein: said optical carrier is provided for use in a communications system having an electrical bandwidth β; and the wavelengths λ 1 and λ 2 are selected to be substantially as close as possible without creating beat frequencies thereof within said bandwidth β.
Claim 13
Dependent Claim
45 words
Apparatus in accordance with claim 9 wherein: said optical carrier is provided for use in a communications system having an electrical bandwidth β; and the wavelengths λ 1 and λ 2 are selected to avoid the occurrence of beat frequencies thereof within said bandwidth β.
Claim 14
Dependent Claim
26 words
Apparatus in accordance with claim 11 further comprising: an optical amplifier coupled to amplify the light from said first light source prior to said combining means.
Claim 15
Dependent Claim
31 words
Apparatus in accordance with claim 12 further comprising: a bandpass filter coupled downstream of said optical amplifier for removing at least a portion of spontaneous emission introduced by said optical amplifier.
Claim 16
Dependent Claim
18 words
Apparatus in accordance with claim 13 wherein said bandpass filter is coupled immediately downstream of said optical amplifier.
Claim 17
Dependent Claim
36 words
Apparatus in accordance with claim 9 further comprising: an external modulator coupled to receive said optical carrier; said external modulator having a modulating input for receiving an information signal to be modulated onto said optical carrier.
Claim 18
Dependent Claim
32 words
Apparatus in accordance with claim 9 further comprising: means for adjusting the phase and amplitude of said error signal to facilitate the reduction of the relative intensity noise in said optical carrier.
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) | 1997-03-07 | 1997-09-06 | 1998-03-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-03-07 | 2001-09-06 | 2002-03-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-03-07 | 2005-09-06 | 2006-03-08 | $7700.00 | Window Closed / Lapsed |