Optical network
First Claim
1. A wavelength division multiplexing optical network, comprising:
- a client;
a plurality of redundant optical paths including a working path and a protection path; and
a plurality of network nodes redundantly connected through said optical paths in a predetermined configuration, at least one of said network nodes being connected to said client, said network nodes transmitting and receiving optical signals with each other at a set of wavelengths, each of said network nodes further comprising;
an optical add/drop multiplexer unit for converting a client optical signal at a first channel frequency from said client to a second channel frequency at one of said wavelengths to generate a converted client optical signal, said add/drop multiplexer unit splitting the converted client optical signal into split and converted redundant client optical signals for said optical paths, said add/drop multiplexer unit selectively multiplexing the split and converted redundant client optical signals to generate a wavelength division multiplexed optical signal, said add/drop multiplexer unit selectively demultiplexing the wavelength division multiplexed optical signal to generate a wavelength division demultiplexed optical signal;
an optical signal failure detector connected to each of said optical paths for detecting a failure in the wavelength division demultiplexed optical signal to generate an optical path failure signal; and
an optical switch unit connected to said optical paths in response to the optical path failure signal and having a first optical switch for switching from one of said optical paths to another of said optical paths.
1 Assignment
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Accused Products
Abstract
A medium-scale IP telecommunications network is configured in a low-cost optical network with good reliability and expandability. A physical configuration example has a center node 2-1 and eight local nodes 2-11 through 2-18 connected in one OADM ring 2-21/2-22. The logical configuration is a star configuration with the central node 2-1 at its origin with all traffic passing through the center node 2-1. The local nodes 2-11 through 2-18 are connected to the central node 2-1 by wavelength-unit optical channels or optical paths λ1 through λ8. Channels are added as required. Initially, for example, the center node 2-1 and the local node 2-5 are connected by λ5, but λ13 can added when the need arises. Since the logical star network is limited to approximately two add/drop optical channels at local nodes, costs are reduced by using inexpensive filters (e.g., dielectric interference film filters or fiber Bragg reflectors) that are capable of extracting only the specific wavelength of the optical channel. High reliability is provided through the use of optical switches for correction of fiber transmission path failures.
77 Citations
33 Claims
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1. A wavelength division multiplexing optical network, comprising:
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a client;
a plurality of redundant optical paths including a working path and a protection path; and
a plurality of network nodes redundantly connected through said optical paths in a predetermined configuration, at least one of said network nodes being connected to said client, said network nodes transmitting and receiving optical signals with each other at a set of wavelengths, each of said network nodes further comprising;
an optical add/drop multiplexer unit for converting a client optical signal at a first channel frequency from said client to a second channel frequency at one of said wavelengths to generate a converted client optical signal, said add/drop multiplexer unit splitting the converted client optical signal into split and converted redundant client optical signals for said optical paths, said add/drop multiplexer unit selectively multiplexing the split and converted redundant client optical signals to generate a wavelength division multiplexed optical signal, said add/drop multiplexer unit selectively demultiplexing the wavelength division multiplexed optical signal to generate a wavelength division demultiplexed optical signal;
an optical signal failure detector connected to each of said optical paths for detecting a failure in the wavelength division demultiplexed optical signal to generate an optical path failure signal; and
an optical switch unit connected to said optical paths in response to the optical path failure signal and having a first optical switch for switching from one of said optical paths to another of said optical paths. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A wavelength division multiplexing optical network, comprising:
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a client;
a plurality of optical paths; and
a plurality of network nodes connected through said optical paths in a predetermined configuration, at least one of said network nodes being connected to said client, said network nodes transmitting and receiving a plurality of optical signals with each other at a set of wavelengths;
a router connected to each of said network nodes for selecting one of said optical paths for transmitting one of the optical signals; and
an optical signal failure detector connected to each of said optical paths and said router for detecting a failure in the optical signal to generate an optical path failure signal for a particular one of said optical paths, wherein said router in response to the optical path failure signal switching from the particular one of said optical paths to another of said optical paths for transmitting the one of the optical signals. - View Dependent Claims (15, 16, 17)
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18. A method of wavelength division multiplexing for an optical network, comprising:
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providing a plurality of redundant optical paths including a working path and a protection path as well as a plurality of network nodes redundantly connected through the optical paths in a predetermined configuration, at least one of the network nodes being connected to a client;
transmitting and receiving optical signals to and from the network nodes at a set of wavelengths, said transmitting and receiving further comprising;
converting a client optical signal at a first channel frequency from the client to a second channel frequency at one of the wavelengths to generate a converted client optical signal;
splitting the converted client optical signal into splitted and converted redundant client optical signals for the optical paths;
selectively multiplexing the splitted and converted redundant client optical signals to generate a wavelength division multiplexed optical signal;
selectively demultiplexing the wavelength division multiplexed optical signal to generate a wavelength division demultiplexed optical signal;
detecting a failure in the wavelength division demultiplexed optical signal to generate an optical path failure signal; and
switching from one of said optical paths to another of said optical paths in response to the optical path failure signal. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. A method of wavelength division multiplexing for an optical network, comprising:
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providing a plurality of optical paths and a plurality of network nodes connected through the optical paths in a predetermined configuration, at least one of said network nodes being connected to a client;
transmitting and receiving a plurality of optical signals among the network nodes at a set of wavelengths;
selecting one of the optical paths for transmitting one of the optical signals for optimal through traffic;
detecting a failure in the optical signal to generate an optical path failure signal for a particular one of the optical paths; and
switching from the particular one of the optical paths to another of the optical paths for transmitting the one of the optical signals in response to the optical path failure signal. - View Dependent Claims (30, 31, 32)
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33. A ring making optical network including a dispersion shifted optical fiber with a wave length in the vicinity of 1552 nm which shows substantially zero chromatic dispersion on at least a part of an optical fiber transmitting path, said optical network comprising:
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a system which transmits a multiplexed optical signal having more than two wave lengths within a wave length range of 1530-1560 nm or the C-band at an interval of 200 GHz wherein an optical input to the dispersion shifted fiber is less than −
3.5 dBm per optical channel, a baud rate of light is less than 2.48 Gbit/s, and a span loss between nodes is less than 12 dB, in other words, an equivalent node interval is less than 40 Km.
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Specification