Optical amplifier and optical transmission system including the optical amplifier
First Claim
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1. An optical amplifier comprising:
- an optical amplifying unit having a gain for wavelength division multiplexed (WDM) signal light obtained by wavelength division multiplexing a plurality of optical signals having different wavelengths;
first control means for detecting an output level of said optical amplifying unit and controlling said optical amplifying unit so that said output level becomes constant;
second control means for detecting said gain according to an input level of said optical amplifying unit and said output level and controlling said optical amplifying unit so that said gain becomes constant; and
selecting means for alternatively selecting and operating said first and second control means in accordance with a predetermined rule.
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Abstract
An optical amplifier relates to WDM (wavelength division multiplexing). The optical amplifier includes an optical amplifying unit, an ALC (automatic output level control) circuit for controlling the unit based on the output level thereof, and AGC (automatic gain control) circuit for controlling the unit based on the input and output levels thereof. A selecting circuit alternatively selects and operates the ALC and AGC circuits in accordance with a predetermined rule. Accordingly, the inconvenience occurring in the case of performing only one of ALC and AGC can be eliminated.
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Citations
49 Claims
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1. An optical amplifier comprising:
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an optical amplifying unit having a gain for wavelength division multiplexed (WDM) signal light obtained by wavelength division multiplexing a plurality of optical signals having different wavelengths; first control means for detecting an output level of said optical amplifying unit and controlling said optical amplifying unit so that said output level becomes constant; second control means for detecting said gain according to an input level of said optical amplifying unit and said output level and controlling said optical amplifying unit so that said gain becomes constant; and selecting means for alternatively selecting and operating said first and second control means in accordance with a predetermined rule. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. An optical transmission system comprising:
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an optical fiber transmission line; and at least one optical amplifier provided in said optical fiber transmission line; said at least one optical amplifier each comprising; an optical amplifying unit having a gain for wavelength division multiplexed (WDM) signal light obtained by wavelength division multiplexing a plurality of optical signals having different wavelengths; first control means for detecting an output level of said optical amplifying unit and controlling said optical amplifying unit so that said output level becomes constant; second control means for detecting said gain according to an input level of said optical amplifying unit and said output level and controlling said optical amplifying unit so that said gain becomes constant; and selecting means for alternatively selecting and operating said first and second control means in accordance with a predetermined rule. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. An apparatus comprising:
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an optical amplifier amplifying a light; an output level controller selectable to control an output level of the optical amplifier to be constant; a gain controller selectable to control gain of the optical amplifier to be constant; and a selector alternately selecting the output level controller and the gain controller. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33, 34, 35)
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36. An apparatus comprising:
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an optical amplifier for amplifying a light; and a controller having a first state in which gain of the optical amplifier is controlled to be constant, and a second state in which an output level of the optical amplifier is controlled to be constant, the controller switching back and forth between the first and second states in accordance with a predetermined switching rule. - View Dependent Claims (37, 38, 39, 40)
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41. A method comprising:
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amplifying a light with an optical amplifier; and switching back and forth between a first state in which a gain of the optical amplifier is controlled to be constant, and a second state in which an output level of the optical amplifier is controlled to be constant. - View Dependent Claims (42, 43)
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44. An apparatus comprising:
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an optical amplifier amplifying a light; and means for switching back and forth between a first state in which a gain of the optical amplifier is controlled to be constant, and a second state in which an output level of the optical amplifier is controlled to be constant.
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45. An optical transmission system comprising:
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an optical fiber transmission line; and at least one optical amplifying unit operatively connected along the optical fiber transmission line, said at least one optical amplifying unit each comprising an optical amplifier for amplifying a light traveling through the optical fiber transmission line, and a controller having a first state in which gain of the optical amplifier is controlled to be constant, and a second state in which an output level of the optical amplifier is controlled to be constant, the controller switching back and forth between the first and second states in accordance with a predetermined switching rule. - View Dependent Claims (46, 47, 48, 49)
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Specification