Patent EP0475016A2 successfully refreshed from Google Patents.
EP0475016A2
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Wavelength-multiplexed optical network system
Assignee: Hitachi Ltd
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Filing: 1991-07-15
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Granted: —
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Expires: 2011-07-15
Abstract
Abstract A wavelength separator in a wavelength-multiplexed optical network system uses a wavelength demultiplexer (2) having optical elements having wavelength selectivity arranged in tandem to directly demultiplex light signals by wavelength without distributing all input light signals. When a node device (A-E, M) is down, a power supply fails or a control signal is not issued, the received light signals are not demultiplexed but propagated through an optical wave-guide (2-1).
Inventors
- 👤 Yasushi Takahashi
- 👤 Katuya Hitachi Daiyon Kyoshinryo A309 Tanaka
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-26 21:49
CPC Classifications
H; H04; H04J; H04J14/00; H04J14/02; H04J14/0201; H04J14/0202; H04J14/0204; H04J14/0205; H04J14/0206
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
119 words
A wavelength-multiplexed optical network system having a plurality of terminals (T) interconnected through node devices (A, B, C, D, E, M) by an optical transmission line (1) for transmitting a plurality of light signals by multiplexed wavelength, comprising: wave separation means (2) for directly demultiplexing a light signal of at least one wavelength of the plurality of wavelength-multiplexed light signals from said optical transmission line; a light receiver (3-1) for supplying the light signal demultiplexed by said wavelength demultiplexing means to a signal processing circuit; and wavelength multiplexing means (2) for multiplexing a light signal converted from the signal of said signal processing circuit by said light receiver with other light signals for transmission to the optical transmission line.
Claim 2
Dependent Claim
28 words
A wavelength-multiplexed optical network system according to Claim 1 wherein said wavelength demultiplexing means and said wavelength multiplexing means are connected in series through an optical wave guide.
Claim 3
Dependent Claim
95 words
A wavelength-multiplexed optical network system according to Claim 1 wherein at least one of said wavelength demultiplexing means and said wavelength multiplexing means comprises a first optical wave guide for coupling said optical transmission line, a second optical wave guide for wavelength demultiplexing or wavelength multiplexing having a portion thereof arranged in the vicinity of said first optical wave guide, and a grating coupler having a parallel-coupling or antiparallel coupling grating arranged between said first optical wave guide and the portion of said second optical wave guide in the vicinity of said first optical guide.
Claim 4
Dependent Claim
43 words
A wavelength-multiplexed optical network system according to Claim 1 wherein said wavelength demultiplexing means demultiplexes a light signal of at least one wavelength of a wavelength preassigned to the node device, an externally designated wavelength and a wavelength requested by the node device.
Claim 5
Dependent Claim
57 words
A wavelength-multiplexed optical network system according to Claim 1 further comprising a control unit for driving said wavelength demultiplexing means, said control unit setting a wavelength to be demultiplexed in accordance with a control signal and causing said wavelength demultiplexing means and said wavelength multiplexing means to bypass the light signal when the control signal is absent.
Claim 6
Dependent Claim
139 words
A wavelength-multiplexed optical network system having a plurality of node devices connected in a ring through an optical transmission line for transmitting light signals of different wavelengths by one or more terminals connected to each of said node devices by wavelength multiplication, one of said node devices comprising means for transmitting a control information signal for designating wavelengths to be used in other node devices, by a signal of a specific wavelength of the wavelength-multiplexed light signals, and each of said other node devices comprising a wavelength demultiplexer for directly demultiplexing the light signal of the wavelength designated by the control information signal from said optical transmission line, and a control circuit for controlling the wavelength to be demultiplexed by said wavelength demultiplexer in accordance with the control information signal transmitted by the light signal of the specific wavelength.
Claim 7
Dependent Claim
142 words
A wavelength-multiplexed optical network system having a plurality of terminals interconnected through node devices by an optical transmission line for transmitting a plurality of light signals by multiplexed wavelengths, each of said node devices comprising: a wavelength demultiplexer including a first optical wave guide connected to said optical transmission line at an input thereof and said optical transmissin line at an output thereof, and a second optical wave guide for demultiplexing a light signal of a specific wavelength from said first optical wave guide through a coupler having wavelength selectivity; and control means for coupling the wavelength to be demultiplexed to said coupler when said terminals and said node device are in operation and coupling said input optical transmission line and said output optical transmission line to bypass the light signals when said terminals and said node device are not in operation.
References Cited (Backward Citations)
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