Wavelength-division multiplexed self-healing passive optical network
First Claim
1. A wavelength-division multiplexed passive optical network including a plurality of subscriber units, a central office having an end connected to a remote node, and said remote node having an end connected to said end of the central office, said network comprising:
- a composite feeder fiber, comprising a working feeder fiber and a protection feeder fiber, for connecting the central office to the remote node;
a reflection unit provided said end of the remote node connected to the central office for reflecting a monitoring optical signal transmitted from the central office;
an output monitor stage provided at said end of the central office connected to the remote node for detecting the reflected monitoring optical signal and generating a control signal based on the presence of abnormality in said composite feeder fiber; and
a first optical switch for switching the working and protection feeder fibers based on said control signalwherein the output monitor stage is provided on the working and protection feeder fibers and the output monitor stage includes;
an output monitor unit for detecting the presence of the monitoring optical signal branched and transmitted from one of the working and protection feeder fibers and transmitting the control signal based on the presence of the abnormality in said composite feeder fiber; and
a first optical circulator for transmitting the monitoring optical signal to the output monitor unit, and transmitting said multiplexed 2N downstream optical signals to said composite feeder fiber.
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Accused Products
Abstract
A wavelength-division multiplexed self-healing passive optical network is capable of detecting cut-off and deterioration of feeder fiber and distribution fiber and restoring a network with a star structure. The network includes a central office, a remote node, and a plurality of subscriber units. Working and protection feeder fibers connect the central office to the remote node. A reflection unit at an end of the remote node connects to the central office for reflecting a monitoring optical signal transmitted from the central office. An output monitor stage at an end of the central office connects to the remote node for detecting the reflected monitoring optical signal and generating a control signal based on the presence of abnormality of the working and protection feeder fibers.
24 Citations
20 Claims
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1. A wavelength-division multiplexed passive optical network including a plurality of subscriber units, a central office having an end connected to a remote node, and said remote node having an end connected to said end of the central office, said network comprising:
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a composite feeder fiber, comprising a working feeder fiber and a protection feeder fiber, for connecting the central office to the remote node; a reflection unit provided said end of the remote node connected to the central office for reflecting a monitoring optical signal transmitted from the central office; an output monitor stage provided at said end of the central office connected to the remote node for detecting the reflected monitoring optical signal and generating a control signal based on the presence of abnormality in said composite feeder fiber; and a first optical switch for switching the working and protection feeder fibers based on said control signal wherein the output monitor stage is provided on the working and protection feeder fibers and the output monitor stage includes; an output monitor unit for detecting the presence of the monitoring optical signal branched and transmitted from one of the working and protection feeder fibers and transmitting the control signal based on the presence of the abnormality in said composite feeder fiber; and a first optical circulator for transmitting the monitoring optical signal to the output monitor unit, and transmitting said multiplexed 2N downstream optical signals to said composite feeder fiber. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A wavelength-division multiplexed passive optical network including a plurality of subscriber units, a central office having an end connected to a remote node, and said remote node having an end connected to said end of the central office, said network comprising:
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a composite feeder fiber, comprising a working feeder fiber and a protection feeder fiber, for connecting the central office to the remote node; and a first optical switch for switching the working and protection feeder fibers, wherein the plurality of subscriber units includes; an upstream light source for transmitting upstream data; a first wavelength-division multiplexer for coupling an upstream optical signal from a subscriber unit of the plurality with an optical signal from an adjacent one of the plural subscriber units, said adjacent one being connected by a protection distribution fiber to said subscriber unit of the plurality; a first optical circulator for transmitting, via the protection distribution fiber, the upstream optical signal to said adjacent one and transmitting upstream an optical signal of said adjacent one transmitted via the protection distribution fiber to the first wavelength-division multiplexer; and a second optical switch for switching such that the upstream light source is connected to the first optical circulator, for rotation of light from said upstream light source, when abnormality of the upstream optical signal of the subscriber unit is detected. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification