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US 6,327,060 B1Granted
Optical transmission system, optically branching apparatus and optical signal processing apparatus
AssigneesKokusai Denshin Denwa Kabushiki Kaisha, KDD Submarine Cable Systems Inc.
InventorsTomohiro Otani, Toshio Kawazawa, Koji Goto
Life of this patent
Estimating the term…
Abstract
In an optical transmission system, an optical transmission line has up and down systems and loops back a supervisory light between the up and down systems. Trunk stations are provided at both ends of the optical transmission line and one or more optically branching units are provided in the optical transmission line for add/dropping a specific wavelength respectively. A branch station is connected to each of one or more the branching units. A bypass line for bypassing the supervisory light is provided in each of the one or more optically branching units.
Claims9
An optical transmission system comprising:
- an optical transmission line having up and down systems, means for looping back a supervisory light between the up and down systems, and an optical branching, unit for adding and dropping a specific wavelength, said optical branching unit having a bypass line for bypassing the supervisory light;
- a trunk station at each end of the optical transmission line;
- and
- a branch station connected to the optical branching unit, wherein the optical branching, unit further comprises in each of the up and down systems:
- a reflecting means for selectively reflecting the specific wavelength;
- means for dropping light of said specific wavelength;
- means for adding light of said specific wavelength;
- and
- first and second optical circulators each having first, second, third and fourth in/out ports, each said circulator adapted for outputting to said second port light inputted into the first port, for outputting to said third port light inputted into the second port, and for outputting to said first port light inputted into the fourth port, the first optical circulator having the first port connected to an up flow side of the optical transmission line, the second port connected to one end of the reflecting means, the third port connected to the means for dropping light, and the fourth port connected to one end of the bypass line, and the second optical circulator having the first port connected to the other end of the reflecting means, the second port connected to a down flow side of the optical transmission line, the third port connected to the other end of the bypass line, and the fourth port connected to the means for adding light, and
- wherein the means for adding light and the means for dropping light each comprise an optical amplifier, and further comprise a first loop back circuit between an output stage of the optical amplifier of the means for dropping light of the up system and an output stage of the optical amplifier of the means for adding light of the down system, and a second loop back circuit between an output stage of the optical amplifier of the means for dropping light of the down system and an output stage of the optical amplifier of the means for adding light of the up system.
7 more elements
An optical transmission system comprising:
- an optical transmission line having an up system and a down system;
- a loop back optical circuit capable of looping back a supervisory light between the up system and the down system;
- an optical branching unit disposed on the optical transmission line having a first optical add/drop device for the up system and a second optical add/drop device for the down system;
- trunk stations at each end of the optical transmission line;
- and
- a branch station connected to the optical branching unit;
- wherein the first optical add/drop device comprises,
- a reflector to selectively reflect a specific wavelength,
- a bypass line,
- an optical input port to add light output from the branch station to be added to the up system,
- an optical output port to drop light dropped from the up system to be applied to the branch station,
- first and second optical couplers each having first, second, third and fourth ports, each said coupler adapted to output to said second port light inputted into the first port, to output to said third port light inputted into the second port, and to output to said first port light inputted into the fourth port, the first optical coupler having the first port connected to an up flow side of the up system in the optical transmission line, the second port connected to an end of the reflector, the third port to output the dropped light toward the output port, and the fourth port connected to an end of the bypass line, and the second optical coupler having the first port connected to another end of the reflector, the second port connected to a down flow side of the up system in the optical transmission line, the third port connected to another end of the bypass line, and the fourth port to receive the added light from the input port.
9 more elements
An optical branching apparatus disposed on an optical transmission line to transmit signal light in a predetermined direction, comprising:
- a reflector to reflect a specific wavelength;
- a bypass line;
- an input port to add light;
- an output port to drop light;
- and
- first and second optical couplers each having first, second, third and fourth ports, each said coupler capable of outputting to said second port light inputted into the first port, to output to said third port light inputted into the second port, and to output to said first port light inputted into the fourth port, the first optical coupler having the first port connected to an up flow side of the optical transmission line, the second port connected to an end of the reflector, the third port connected to the output port, and the fourth port connected to an end of the bypass line, and the second optical coupler having the first port connected to another end of the reflector, the second port connected to a down flow side of the optical transmission line, the third port connected to another end of the bypass line, and the fourth port connected to the input port.
3 more elements
Dependencies are inferred from the claim text.