EP0762569A2
Expired / Lapsed
EP
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Method and apparatus for controlling optical amplifier used for optically amplifying wavelength-division multiplexed signal
Assignee: Fujitsu Ltd
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Filing: 1996-08-23
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Granted: —
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Expires: 2016-08-23
Abstract
Abstract A method and apparatus for controlling gain differences between optical signals, and hence an output of each individual optical signal, in an optical amplifier including a rare-earth-doped fiber for optically amplifying a wavelength-division multiplexed signal. Pumping light is injected into an erbium-doped fiber that is also supplied with additional pumping light that gives a different gain characteristic to the erbium-doped fiber. The output of each signal light is detected by a photodetector, and based on the detected output, injection power is controlled individually for each pumping light.
Inventors
- 👤 Shinya c/o Fujitsu Ltd. Inagaki
- 👤 Kenji c/o Fujitsu Ltd. Tagawa
- 👤 Norifumi c/o Fujitsu Hokkaido Digital Shukunami
- 👤 Nobuhiro c/o Fujitsu Ltd. Fukushima
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 17:09
CPC Classifications
H; H04; H04B; H04B10/00; H04B10/29; H04B10/291; H04B10/2912; H01; H01S; H01S3/00; H01S3/10; H01S3/13; H01S3/1301; H01S3/13013; H04B10/293; H04B10/294; H04B10/2942; H04B10/296; H04J; H04J14/00; H04J14/02; H04J14/0221; H01S3/05; H01S3/06; H01S3/063; H01S3/067; H01S3/06754; H01S3/09; H01S3/091; H01S3/094; H01S3/094003; H01S3/094011; H01S3/094096
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
87 words
A method of controlling an optical amplifier including a rare-earth-doped fiber for optically amplifying a wavelength-division multiplexed signal carrying a plurality of optical signals at different wavelengths, comprising the steps of: injecting first pumping light into the rare-earth-doped fiber; injecting second pumping light into the rare-earth-doped fiber, the second pumping light giving a different gain characteristic to the rare-earth-doped fiber from a gain characteristic that the first pumping light gives; and controlling an injection power for at least one of the first and the second pumping lights.
Claim 2
Dependent Claim
53 words
A method according to claim 1, further comprising the step of detecting respective powers of the plurality of optical signals at an output of the optical amplifier, wherein, in the controlling step, the injection powers of the first and the second pumping lights are controlled in accordance with the detected optical signal powers.
Claim 3
Dependent Claim
40 words
A method according to claim 2, wherein, in the controlling step, the injection powers of the first and the second pumping lights are controlled by controlling drive currents to the light sources of the first and the second pumping lights.
Claim 4
Dependent Claim
49 words
A method according to claim 2, wherein, in the controlling step, the injection powers of the first and the second pumping lights are controlled by controlling a variable optical attenuator provided between the rare-earth-doped fiber and each of the light sources of the first and the second pumping lights.
Claim 5
Independent Claim
79 words
A method of controlling an optical amplifier including a rare-earth-doped fiber for optically amplifying a wavelength-division multiplexed signal carrying a plurality of optical signals at different wavelengths, comprising the steps of: injecting control light into the rare-earth-doped fiber, the control light being at a wavelength within a wavelength region where the rare-earth-doped fiber exhibits an optical amplification effect; and controlling injection power or wavelength of the control light, thereby controlling a gain difference between the plurality of optical signals.
Claim 6
Dependent Claim
27 words
A method according to claim 5, wherein the wavelength of the control light is different from the wavelength of any one of the plurality of optical signals.
Claim 7
Dependent Claim
32 words
A method according to claim 6, wherein the wavelength of the control light falls within a wavelength region where an emission probability in the rare-earth-doped fiber is greater than an absorption probability.
Claim 8
Dependent Claim
29 words
A method according to claim 7, wherein the rare-earth-doped fiber is an erbium-doped fiber, and the wavelength of the control light is equal to or longer than 1520 nm.
Claim 9
Dependent Claim
39 words
A method according to claim 8, wherein the wavelengths of the plurality of optical signals are within a range from 1530 to 1565 nm, and the wavelength of the control light is equal to or longer than 1565 nm.
Claim 10
Dependent Claim
22 words
A method according to claim 6, further comprising the step of removing the control signal at an output of the optical amplifier.
Claim 11
Dependent Claim
22 words
A method according to claim 6, wherein the control light is modulated with a supervisory signal used to supervise a transmission channel.
Claim 12
Dependent Claim
16 words
A method according to claim 5, wherein the control signal is the wavelength-division multiplexed signal itself.
Claim 13
Dependent Claim
51 words
A method according to claim 5, further comprising the step of detecting respective powers of the plurality of optical signals at an output of the optical amplifier, wherein, in the controlling step, the injection power or wavelength of the control light is controlled in accordance with the detected optical signal powers.
Claim 14
Independent Claim
98 words
An apparatus for controlling an optical amplifier including a rare-earth-doped fiber for optically amplifying a wavelength-division multiplexed signal carrying a plurality of optical signals at different wavelengths, comprising: a first optical coupler for injecting first pumping light into the rare-earth-doped fiber; a second optical coupler for injecting second pumping light into the rare-earth-doped fiber, the second pumping light giving a different gain characteristic to the rare-earth-doped fiber from a gain characteristic that the first pumping light gives; and a control circuit for controlling an injection power of at least one of the first and the second pumping lights.
Claim 15
Dependent Claim
50 words
An apparatus according to claim 14, further comprising means for detecting respective powers of the plurality of optical signals at an output of the optical amplifier, wherein the control circuit controls the injection powers of the first and the second pumping lights in accordance with the detected optical signal powers.
Claim 16
Dependent Claim
37 words
An apparatus according to claim 15, wherein the control circuit controls the injection powers of the first and the second pumping lights by controlling drive currents to light sources of the first and the second pumping lights.
Claim 17
Dependent Claim
46 words
An apparatus according to claim 15, wherein the control circuit controls the injection powers of the first and the second pumping lights by controlling a variable optical attenuator provided between the rare-earth-doped fiber and each of light sources of the first and the second pumping light.
Claim 18
Independent Claim
84 words
An apparatus for controlling an optical amplifier including a rare-earth-doped fiber for optically amplifying a wavelength-division multiplexed signal carrying a plurality of optical signals at different wavelengths, comprising: an optical coupler for injecting control light into the rare-earth-doped fiber, the control light being at a wavelength within a wavelength region where the rare-earth-doped fiber exhibits an optical amplification effect; and a control circuit for controlling injection power or wavelength of the control light, thereby controlling a gain difference between the plurality of optical signals.
Claim 19
Dependent Claim
27 words
An apparatus according to claim 18, wherein the wavelength of the control light is different from the wavelength of any one of the plurality of optical signals.
Claim 20
Dependent Claim
32 words
An apparatus according to claim 19, wherein the wavelength of the control light falls within a wavelength region where an emission probability in the rare-earth-doped fiber is greater than an absorption probability.
Claim 21
Dependent Claim
29 words
An apparatus according to claim 20, wherein the rare-earth-doped fiber is an erbium-doped fiber, and the wavelength of the control light is equal to or longer than 1520 nm.
Claim 22
Dependent Claim
39 words
An apparatus according to claim 21, wherein the wavelengths of the plurality of optical signals are within a range from 1530 to 1565 nm, and the wavelength of the control light is equal to or longer than 1565 nm.
Claim 23
Dependent Claim
21 words
An apparatus according to claim 19, further comprising means for removing the control signal at an output of the optical amplifier.
Claim 24
Dependent Claim
22 words
An apparatus according to claim 19, wherein the control light is modulated with a supervisory signal used to supervise a transmission channel.
Claim 25
Dependent Claim
16 words
An apparatus according to claim 18, wherein the control signal is the wavelength-division multiplexed signal itself.
Claim 26
Dependent Claim
49 words
An apparatus according to claim 18, further comprising means for detecting the respective powers of the plurality of optical signals at an output of the optical amplifier, wherein the control circuit controls the injection power or wavelength of the control light in accordance with the detected optical signal powers.
References Cited (Backward Citations)
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