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EP0924884A2
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Optical node, optical wavelength multiplexing and demultiplexing method, and optical transmission system
Assignee: NEC Corp
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Filing: 1998-12-08
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Granted: —
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Expires: 2018-12-08
Abstract
Abstract Wavelength multiplexed optical signals input at an input terminal 11 initially pass through an optical circulator. Then, a first optical signal having a specific wavelength is transmitted through an optical filter 17 and is output at an output terminal 12. The remaining first optical signals reflected by the optical filter 17 pass through optical circulators 15 and 16, and are then combined with an optical signal input at an input terminal 14 by an optical filter 18. Thereafter the resultant signals are output at an output terminal 13. <IMAGE>
Inventors
- 👤 Hiroyuki Kato
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 15:00
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/24; G02B6/26; G02B6/28; G02B6/293; G02B6/29379; G02B6/2938; G02B6/29304; G02B6/29316; G02B6/29317; G02B6/29319; G02B6/2932; G02B6/29392; G02B6/29394
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
97 words
An optical node device for dropping a first preassigned
optical signal from and inserting a second preassigned
optical signal into a wavelength multiplexed optical signal
comprising: a first optical filter for dividing said wavelength
multiplexed optical signal into said first preassigned
optical signal and a remaining optical signal; and a second optical filter for multiplexing said remaining
optical signal and said second preassigned optical signal, wherein said first and second optical filters are
disposed so that said first and second preassigned optical
signals do not coincide with each other on either said first
or second optical filter.
Claim 2
Dependent Claim
21 words
The optical node device as defined in claim 1, wherein
said first and second preassigned optical signals have the
same wavelength.
Claim 3
Dependent Claim
63 words
The optical node device as defined in claim 1 or 2, further
comprising a first optical circulator and a second optical
circulator, wherein said first and second optical circulators
are disposed between said first and second optical filters
and connected so that said remaining optical signal goes
through said first optical circulator, said second optical
circulator and said second optical filter in sequence.
Claim 4
Dependent Claim
25 words
The optical node device as defined in claim 3, further
comprising an optical attenuator inserted between said second
optical circulator and said second optical filter.
Claim 5
Dependent Claim
33 words
The device as defined in claim 1, 2, 3, or 4, wherein
at least one of said first and second optical filters delays
incident light with a monotonously changing delay according
to wavelength.
Claim 6
Independent Claim
30 words
The device as defined in any one of claims 1 to 5, wherein
at least one of said first and second optical filters
comprises a plurality of cascaded optical filters.
Claim 7
Dependent Claim
45 words
The optical node device as defined in claim 6, wherein
said plurality of optical filters are arranged in order of
reflection wavelength and said wavelength multiplexed optical
signal is fisrt incident on a one of said plurality of
optical filters having the largest reflection wavelength.
Claim 8
Dependent Claim
22 words
The optical node device as defined in claim 6 or 7, wherein
each of said plurality of optical filters possesses different
reflectivities.
Claim 9
Independent Claim
28 words
The device as defined in any one of claims 1 to 8, wherein
at least one of said first and said second optical filters
comprises a fiber grating.
Claim 10
Independent Claim
32 words
The device as defined in any one of claims 1 to 9, wherein
at least one of said first and second optical filters
comprises an optical filter having a dielectric multi-layer
film.
Claim 11
Independent Claim
31 words
The device as defined in any one of claims 1 to 10, wherein
at least one of said first and second optical filters
comprises an optical filter having a Fabry-Pérot
interferometer.
Claim 12
Dependent Claim
28 words
The device as defined in claim 9, 10, or 11, further
comprising a controller for adjusting a center wavelength of
one of said first and second optical filters.
Claim 13
Dependent Claim
59 words
An optical signal multiplexing/demultiplexing method
comprising the steps of: separating an input wavelength multiplexed optical
signal into a first optical signal having a first
predetermined wavelength and a first remaining optical
signal; and selecting a second optical signal having second
predetermined wavelengths from input optical signal and one
of said first optical signal and said first remaining optical
signal.
Claim 14
Dependent Claim
21 words
The optical wavelength multiplexing/demultiplexing
method as defined in claim 13, wherein said first and second
predetermined wavelengths have the same value.
Claim 15
Dependent Claim
109 words
An optical transmission system comprising: a plurality of optical node devices; and at least one optical fiber transmission path along which
said plurality of optical node devices are interconnected, wherein each of said plurality of node devices
comprises: a first optical filter for dividing input wavelength
multiplexed optical signal into a first preassigned optical
signal and a remaining optical signal; and a second optical filter for multiplexing said remaining
optical signal and a second preassigned optical signal, wherein said first and second optical filters are
disposed so that said first and second preassigned optical
signals do not coincide with each other on either said first
or second optical filter.
Claim 16
Dependent Claim
22 words
The optical transmission system as defined in claim 15,
wherein said plurality of optical node devices are connected
in a ring shape.
Claim 17
Dependent Claim
21 words
The optical transmission system as defined in claim 15 or 16,
further comprising an optical transmitter for transmitting an
optical signal.
Claim 18
Dependent Claim
144 words
An optical add/drop multiplexing device, comprising: a first optical circulator having an input port for
receiving an input signal, an output port, and an
input/output port; a second optical circulator having an input port, an
output port for providing an output signal, and an
input/output port, said input port of said second circulator
being connected to said output port of said first circulator; a first filter means connected to said input/output port
of said first circulator for filtering the input signal to
pass a first signal with a first wavelength and reflect a
remainder signal back to said first circulator; an output terminal connected to said first filter for
outputting the first signal; a second filter means connected to said input/output
port of said second circulator for multiplexing a second
signal and the remainder signal; and an input terminal for receiving the second signal.
References Cited (Backward Citations)
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