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US 6,055,092 AGranted
Multi-wavelength light amplifier
AssigneeFujitsu Limited
InventorsYasushi Sugaya, Miki Takeda, Susumu Kinoshita, Terumi Chikama
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Abstract
A multi-wavelength light amplifier includes a first-stage light amplifier which has a first light amplifying optical fiber amplifying a light input, a second-stage light amplifier which has a second light amplifying optical fiber amplifying a first light output from the first-stage light amplifier, and an optical system which maintains a second light output of the second-stage light amplifier at a constant power level. The first-stage and second-stage light amplifiers have different gain vs wavelength characteristics so that the multi-wavelength light amplifier has no wavelength-dependence of a gain thereof.
Claims30
An apparatus comprising:
- a multi-stage optical amplifying unit, for amplifying an input light, which includes
- a first-stage optical amplifier which has an optical fiber for amplifying the input light to produce a first-stage amplified light;
- a second-stage optical amplifier which has an optical fiber for amplifying the first-stage amplified light, to produce a second-stage amplified light;
- and
- an attenuator positioned between the first-stage optical amplifier and the second-stage optical amplifier, to attenuate the power level of the first-stage amplified light and thereby control a power level of the second-stage amplified light.
2 more elements
An apparatus comprising:
- a multi-stage optical amplifying unit, for amplifying an input light, which includes
- a first-stage optical amplifier which has an optical fiber for amplifying the input light, to produce a first-stage amplified light;
- a second-stage optical amplifier which has an optical fiber for amplifying the first-stage amplified light, to produce a second-stage amplified light;
- and
- a level controller controlling the power level of the first-stage amplified light based on a power level of the second-stage amplified light.
2 more elements
An apparatus comprising:
- a multi-stage optical amplifying unit, for amplifying an input light, which includes
- a first-stage optical amplifier which has an optical fiber for amplifying the input light, to produce a first-stage amplified light;
- a second-stage optical amplifier which has an optical fiber for amplifying the first-stage amplified light, to produce a second-stage amplified light;
- and
- a level controller including an attenuator positioned between the first-stage optical amplifier and the second-stage optical amplifier, to control a power level of the first-stage amplified light depending on a power level of the second-stage amplified light.
2 more elements
A method comprising the steps of:
- (a) optically amplifying an input light to produce a first-stage amplified light;
- (b) optically amplifying the first-stage amplified light to produce a second-stage amplified light;
- (c) controlling the power level of the first-stage amplified light in accordance with a power level of the second-stage amplified light;
- and
- (d) performing said steps (a), (b) and (c) by a multi-stage optical amplifying unit.
2 more elements
An apparatus comprising:
- a multi-stage optical amplifying unit, for amplifying an input light, which includes:
- a first-stage optical amplifier which has an optical fiber for amplifying the input light, to produce a first-stage amplified light;
- a second-stage optical amplifier which has an optical fiber for amplifying the first-stage amplified light, to produce a second-stage amplified light;
- and
- a level controller detecting a power level of the second-stage amplified light, and controlling the power level of the first-stage amplified light in accordance with said detected power level.
2 more elements
An apparatus comprising:
- a multi-stage optical amplifying unit, for amplifying an input light, which includes:
- a first-stage optical amplifier which has an optical fiber for amplifying the input light, to produce a first-stage amplified light;
- a second-stage optical amplifier which has an optical fiber for amplifying the first-stage amplified light, to produce a second-stage amplified light at an output port of the second-stage optical amplifier;
- and
- a level controller controlling a power level of the first-stage amplified light based on a power level of the second-stage amplified light at the output port of the second-stage optical amplifier.
2 more elements
An apparatus comprising:
- a multi-stage optical amplifying unit, for amplifying an input light, which includes
- a first-stage optical amplifier amplifying the input light, to produce a first-stage amplified light;
- a second-stage optical amplifier amplifying the first-stage amplified light, to produce a second-stage amplified light;
- a detector detecting a power level of the second-stage amplified light;
- and
- an optical attenuator having a variable attenuation and positioned between the first-stage optical amplifier and the second-stage optical amplifier to attenuate the first-stage amplified light, the attenuation of the optical attenuator being controlled based on the power level detected by the detector.
3 more elements
A method comprising the steps of:
- (a) optically amplifying an input light to produce a first-stage amplified light;
- (b) optical amplifying the first-stage amplified light to produce a second-stage amplified light;
- (c) attenuating a power level of the first-stage amplified light in accordance with a power level of the second-stage amplified light;
- and
- (d) performing said steps (a), (b) and (c) by a multi-stage optical amplifying unit.
2 more elements
A method comprising the steps of:
- (a) providing a multi-stage optical amplifying unit;
- (b) optically amplifying an input light by a stage of the multi-stage optical amplifying unit to produce a first-stage amplified light;
- (c) optical amplifying the first-stage amplified light by a stage of the multi-stage optical amplifying unit, different from said stage in step (b), to produce a second-stage amplified light;
- (d) attenuating the power level of the first-stage amplified light in accordance with a power level of the second-stage amplified light, by the multi-stage optical amplifying unit;
- and
- (e) outputting the second-stage amplified light as an output light of the multi-stage optical amplifying unit.
3 more elements
A method comprising the steps of:
- (a) transmitting an optical signal through an optical fiber;
- (b) providing a multi-stage optical amplifying unit;
- (c) optically amplifying the optical signal received through the optical fiber by a stage of the multi-stage optical amplifying unit, to produce a first-stage amplified optical signal;
- (d) optically amplifying the first-stage amplified optical signal by a stage of the multi-stage optical amplifying unit different from said stage in step (c), to produce a second-stage amplified optical signal;
- (e) controlling the power level of the first-stage amplified optical signal in accordance with a power level of the second-stage amplified optical signal by the multi-stage optical amplifying unit;
- (f) outputting the second-stage amplified optical signal as an output optical signal of the multi-stage optical amplifying unit;
- and
- (g) transmitting the output optical signal through an optical fiber.
5 more elements
Dependencies are inferred from the claim text.