US5764404A
Expired / Lapsed
US
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Wavelength-division-multiplexing optical amplifier
Assignee: Fujitsu Ltd
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Filing: 1995-07-28
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Granted: 1998-06-09
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Expires: 2015-07-28
Abstract
Abstract An optical amplifier amplifies a wavelength division-multiplexed optical input signal composed of optical signals having different wavelengths such that the output level of each of the optical signal is always optimized and such that the difference between the gains of the amplifier on the optical signals is minimized when the number of optical signals is two. The output level of the amplifier is controlled according to the number of the optical signals, to optimize the output level of each of the optical signals.
Inventors
- 👤 Kazuo Yamane
- 👤 Michikazu Shima
- 👤 Yumiko Kawasaki
- 👤 Kenji Tagawa
- 👤 Shinya Inagaki
- 👤 Norifumi Shukunami
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 10:59
CPC Classifications
H; H04; H04B; H04B10/00; H04B10/29; H04B10/291; H04B10/293; H04B10/294; H04B10/296; H01; H01S; H01S3/00; H01S3/10; H01S3/10007; H01S3/1001; H01S3/13; H01S3/1301; H01S3/13013; H04B10/2942; H04J; H04J14/00; H04J14/02; H04J14/0221; H01S2301/00; H01S2301/04; H01S2302/00; H01S2303/00; H01S3/05; H01S3/06; H01S3/063; H01S3/067; H01S3/06754; H01S3/09; H01S3/091; H01S3/094; H01S3/094096; H01S3/10015; H01S3/1305
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
122 words
An optical amplifier in an apparatus for amplifying a wavelength-division-multiplexed optical input signal, said input signal being composed of optical signal channels having respective wavelength bands, comprising: means for providing a reference value that varies according to a number of channels conveying optical signals to be amplified, in response to detection of the presence of signals in the channels; means for detecting a signal level of the wavelength division-multiplexed signal output from the optical amplifier; and means for controlling the output level of the amplifier in dependence upon a comparison between the detected signal level and the reference value, the level of the optical output of the amplifier being controlled according to the number of the optical signal channels having signals present.
Claim 2
Dependent Claim
122 words
An optical amplifier in an apparatus for amplifying a wavelength-division-multiplexed optical input signal, said input signal being composed of optical signal channels having respective wavelength bands, comprising: means for providing a reference value that varies according to a number of channels conveying optical signals to be amplified, in response to detection of the presence of signals in the channels; means for detecting a signal level of the wavelength division-multiplexed signal output from the optical amplifier; and means for controlling the output level of the amplifier in dependence upon a comparison between the detected signal level and the reference value, the level of the optical output of the amplifier being controlled according to the number of the optical signal channels having signals present.
Claim 3
Dependent Claim
27 words
The optical amplifier according to claim 1, wherein the level of the optical output of the amplifier is controlled by controlling the strength of an excitation beam.
Claim 4
Dependent Claim
33 words
The optical amplifier according to claim 1, wherein the level of the optical output of the amplifier is controlled so that each of the optical signals is kept at a given output level.
Claim 5
Dependent Claim
25 words
The optical amplifier according to claim 1, wherein the external reference input corresponding to the number of the optical signals is set through a switch.
Claim 6
Dependent Claim
40 words
The optical amplifier according to claim 1, wherein said channels of the input signal are demultiplexed through a filter, and the respective channels are checked to see if optical signals are present, the number of the optical signals being determined.
Claim 7
Dependent Claim
69 words
The optical amplifier according to claim 1, wherein the optical signal channels are modulated with different frequencies, respectively, and are multiplexed into the wavelength-division-multiplexed optical input signal, the input signal is converted into an electric signal, the electric signal is separated into modulation frequency components, and the modulation frequency components are checked to see if said modulation frequencies are present, to thereby determine the number of the optical signals.
Claim 8
Dependent Claim
28 words
The optical amplifier according to claim 6, wherein the modulation frequencies are selected to suppress induced Brillouin scattering in an optical fiber that transmits the wavelength-division-multiplexed optical signal.
Claim 9
Independent Claim
90 words
An apparatus including an optical amplifier which amplifies a wavelength-division-multiplexed signal having a plurality of signal channels in respective wavelength hands, comprising: means for providing a reference value that varies according to the number of channels conveying signals to be amplified in response to the presence of signals in then channels; means for detecting a signal level of the wavelength-division-multiplexed signal output from the optical amplifier; and means for controlling the output level of the amplifier in dependence upon a comparison between the detected signal level and the reference value.
Claim 10
Independent Claim
90 words
An apparatus including an optical amplifier which amplifies a wavelength-division-multiplexed signal having a plurality of signal channels in respective wavelength hands, comprising: means for providing a reference value that varies according to the number of channels conveying signals to be amplified in response to the presence of signals in then channels; means for detecting a signal level of the wavelength-division-multiplexed signal output from the optical amplifier; and means for controlling the output level of the amplifier in dependence upon a comparison between the detected signal level and the reference value.
Claim 11
Independent Claim
108 words
An apparatus including an optical amplifier which amplifies a wavelength-division-multiplexed signal having a plurality of signal channels in respective wavelength bands, comprising: means for providing a reference value that varies according to the number of channels conveying signals to be amplified in response to the presence of signals in the channels; means for detecting a signal level of the wavelength-division-multiplexed signal output from the optical amplifier; and means for controlling the output level in dependence upon a comparison between the detected signal level and the reference value such that the gain of the optical amplifier is reduced in correspondence to the number of channels conveying signals that fail.
Claim 12
Independent Claim
108 words
An apparatus including an optical amplifier which amplifies a wavelength-division-multiplexed signal having a plurality of signal channels in respective wavelength bands, comprising: means for providing a reference value that varies according to the number of channels conveying signals to be amplified in response to the presence of signals in the channels; means for detecting a signal level of the wavelength-division-multiplexed signal output from the optical amplifier; and means for controlling the output level in dependence upon a comparison between the detected signal level and the reference value such that the gain of the optical amplifier is reduced in correspondence to the number of channels conveying signals that fail.
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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) | 2001-06-08 | 2001-12-08 | 2002-06-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-06-08 | 2005-12-08 | 2006-06-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-06-08 | 2009-12-08 | 2010-06-09 | $7700.00 | Window Closed / Lapsed |