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US 5,859,938 AGranted
Optical amplifier and optical transmission system
AssigneeFujitsu Limited
InventorsYoshio Nabeyama, Kazuyuki Tanikawa, Mitsuo Kitamura
Life of this patent
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Abstract
An optical amplifier with redundant excitation light sources for exciting a rare earth doped optical fiber such as an EDF (Erbium Dope Fiber) minimizes the loss of the excitation light so as to introduce the excitation light to the EDF effectively, though an optical coupler, which plural optical fibers for transmitting the excitation lights from plural excitation light sources are welded, is used. And, the optical amplifier keeps the total of the excitation light introduced to the EDF at a predetermined value and changes one excitation light source to the other unless the output total from the respective excitation light sources becomes zero.
Claims24
An optical amplifier comprising:
- a rare earth doped optical fiber excited by excitation lights and amplifying an optical signal input to the rare earth doped optical fiber;
- a first excitation light source and a second light source outputting said excitation lights;
- an optical coupler combining said excitation lights output from said first excitation light source and said second excitation light source together and equally dividing the combined excitation lights into at least two divided excitation lights;
- a first excitation light coupler introducing one of said divided excitation lights to one end of said rare earth doped optical fiber;
- and
- a second excitation light coupler introducing a different one of said divided excitation lights to another end of said rare earth doped optical fiber.
3 more elements
An optical transmission system, comprising:
- a terminal station providing an optical signal to one end of an optical fiber line;
- and
- a repeater connected to another end of the optical fiber line and amplifying the optical signal provided to the optical fiber line by the terminal station, the repeater including
- a rare earth doped optical fiber having first and second ends, and
- an optical coupler, optically connected to a first light source and a second light source which produce a first excitation light and a second excitation light, respectively, the optical coupler combining the first and second excitation lights together and equally dividing the combined excitation lights into at least two divided excitation lights, one of said at least two divided excitation lights being provided to the first end of the rare earth doped optical fiber and another of said at least two divided excitation lights being provided to the second end of the rare earth doped optical fiber, for amplifying the optical signal.
2 more elements
An optical transmission system, comprising:
- a repeater connected to an optical fiber line and amplifying an optical signal travelling through the optical fiber line, the repeater including
- a rare earth doped optical fiber having first and second ends, and
- an optical coupler, optically connected to a first light source and a second light source which produce a first excitation light and a second excitation light, respectively, the optical coupler combining the first and second excitation lights together and equally dividing the combined excitation lights into at least two divided excitation lights, one of said at least two divided excitation lights being provided to the first end of the rare earth doped optical fiber and another of said at least two divided excitation lights being provided to the second end of the rare earth doped optical fiber, for amplifying the optical signal;
- and
- a terminal station receiving the amplified optical signal from the optical fiber line.
2 more elements
An optical transmission system, comprising:
- a output terminal station providing an optical signal to an optical fiber line;
- a repeater amplifying the optical signal as the optical signal travels through the optical fiber line;
- and
- a receiving terminal station receiving the amplified optical signal from the optical fiber line, wherein the repeater includes
- a rare earth doped optical fiber having first and second ends, and
- an optical coupler, optically connected to a first light source and a second light source which produce a first excitation light and a second excitation light, respectively, the optical coupler combining the first and second excitation lights together and equally dividing the combined excitation lights into at least two divided excitation lights, one of said at least two divided excitation lights being provided to the first end of the rare earth doped optical fiber and another of said at least two divided excitation lights being provided to the second end of the rare earth doped optical fiber, for amplifying the optical signal.
3 more elements
An apparatus comprising:
- a rare earth doped optical fiber having two ends;
- and
- an optical coupler, optically connected to a first light source and a second light source which produce first and second excitation lights, respectively, the optical coupler combining the first and second excitation lights together and equally dividing the combined excitation lights into at least two light beams, at least one of said at least two light beams being provided to each end of the rare earth doped optical fiber.
An optical amplifier comprising:
- a rare earth doped optical fiber having first and second ends, an optical signal travelling through the optical fiber from the first end to the second end;
- first and second excitation light sources producing first and second excitation lights, respectively;
- an optical coupler combining the first and second excitation lights into a combined light, and equally dividing the combined light into first and second divided excitation lights;
- a first light coupler introducing the first divided excitation light to the optical fiber through the first end of the optical fiber;
- and
- a second light coupler introducing the second divided excitation light to the optical fiber through the second end of the optical fiber, the first and second divided excitation lights exciting the optical fiber and thereby amplifying the optical signal as the optical signal travels through the optical fiber.
3 more elements
An optical amplifier comprising:
- a rare earth doped optical fiber having first and second ends, an optical signal travelling through the optical fiber from the first end to the second end;
- an optical coupler combining first and second excitation lights into a combined light, and equally dividing the combined light into first and second divided excitation lights, wherein
- the first and second divided excitation lights are introduced to the optical fiber through the first end and second ends, respectively, of the optical fiber, to amplify the optical signal as the optical signal travels through the optical fiber.
Dependencies are inferred from the claim text.