Optical: systems and elements – Deflection using a moving element – Using a periodically moving element
Reexamination Certificate
1998-01-16
2001-10-02
Pascal, Leslie (Department: 2633)
Optical: systems and elements
Deflection using a moving element
Using a periodically moving element
C359S199200, C359S199200
Reexamination Certificate
active
06297895
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a wavelength division multiplexing system, a wavelength division multiplexing transmission system, and an optical path cross connection system.
BACKGROUND OF THE INVENTION
Optical wavelength division multiplexing (hereinafter also referred to as ‘wavelength multiplexing’) systems are generally used to transmit signal lights with different wavelengths on an optical transmission line so as to enchance the transmission capacity. In the wavelength division multiplexing systems, multiplexing at a transmitter and demultiplexing at a receiver are needed and multiplex and demultiplex losses occur at the transmitter and receiver, respectively.
However, in the conventional wavelength division multiplexing systems using the wavelength multiplexing and demultiplexing, wavelength multiplexing and demultiplexing couplers that are needed are difficult to fabricate. This is because the wavelength interval between adjacent signal lights is so narrow.
On the other hand, in the conventional wavelength division multiplexing system employing the directional coupler, the demultiplex and multiplex losses are substantial. This is because the demultiplexing or multiplexing by the directional coupler causes a theoretical demultiplex or multiplex loss.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the invention to provide a wavelength multiplexing transmission system where wavelength multiplexing and demultiplexing couplers are easy to fabricate.
It is a further object of the invention to provide a wavelength multiplexing transmission system where multiplex and demultiplex losses can be reduced.
According to the invention, provided is a method for wavelength-multiplexing signal lights with three or more wavelengths, wherein: a wavelength arrangement is made by providing at least a wavelength block of signal light with one wavelength and a wavelength block where signal lights with two or more wavelengths are wavelength-multiplexed or providing a plurality of wavelength blocks where signal lights with two or more wavelengths are wavelength-multiplexed, and by setting a wavelength interval between adjacent wavelength blocks to be wider than a wavelength interval between signal lights in a wavelength block.
According to another aspect of the invention, provided is a wavelength multiplexing transmission system for transmitting signal lights with three or more wavelengths through an optical fiber transmission line, wherein: a wavelength arrangement is made by providing at least a wavelength block of signal light with one wavelength and a wavelength block where signal lights with two or more wavelengths are wavelength-multiplexed or providing a plurality of wavelength blocks where signal lights with two or more wavelengths are wavelengths-multiplexed, and by setting a wavelength interval between adjacent wavelength blocks to be wider than a wavelength interval between signal lights in a wavelength block.
According to another aspect of the invention, provided is an optical path cross connection system for exchanging wavelength-multiplexed signal light where signal lights with three or more wavelengths are wavelength-multiplexed, wherein: a wavelength arrangement is made by providing at least a wavelength block of signal light with one wavelength and a wavelength block where signal lights with two or more wavelengths are wavelength-multiplexed or providing a plurality of wavelength blocks where signal lights with two or more wavelengths are wavelength-multiplexed, and by setting a wavelength interval between adjacent wavelength blocks to be wider than a wavelength interval between signal lights in a wavelength block.
In this invention, the wavelength arrangement of signal light is made with unequal wavelength interval, but a wavelength block composed of single wavelength or several wavelengths with a narrow interval, where the wavelength interval between adjacent wavelength blocks is set to be wider than the wavelength interval in the wavelength block.
Therefore, the multiplexer and demultiplexer in the wavelength multiplexing transmission system of the invention can use partially a wavelength multiplexing and demultiplexing coupler. Namely, the number of directional coupler can be reduced and the multiplex and demultiplex losses can be thereby reduced.
REFERENCES:
patent: 4466694 (1984-08-01), MacDonald
patent: 5121453 (1992-06-01), Orazi et al.
patent: 5170451 (1992-12-01), Ohshima
patent: 5177803 (1993-01-01), Newhouse et al.
patent: 5467212 (1995-11-01), Huber
patent: 5479547 (1995-12-01), Kunikane et al.
patent: 5612805 (1997-03-01), Fevrier et al.
patent: 5646399 (1997-07-01), Fukushima et al.
patent: 5764821 (1995-11-01), Glance
patent: 5771112 (1998-06-01), Hamel et al.
patent: 5801858 (1998-09-01), Roberts et al.
patent: 5905827 (1999-05-01), Naganuma et al.
patent: 5917625 (1999-06-01), Ogusu et al.
patent: 5936763 (1999-08-01), Mitsuda et al.
patent: 6084694 (2000-07-01), Milton et al.
patent: 6091538 (2000-07-01), Takeda et al.
patent: 56-150706 (1981-11-01), None
patent: 57-14806 (1982-01-01), None
patent: 2-87841 (1990-03-01), None
patent: 02-87841 (1990-03-01), None
patent: 4-37225 (1992-02-01), None
patent: 4-220602 (1992-08-01), None
patent: 4-220603 (1992-08-01), None
patent: 5-292558 (1993-11-01), None
patent: 6-252890 (1994-09-01), None
patent: 6-258545 (1994-09-01), None
patent: 6-311108 (1994-11-01), None
patent: 7-231305 (1995-08-01), None
patent: 62-35084 (1997-07-01), None
Japanese Office Action, dated Nov. 30, 1999, with English language translation of Japanese Examiner's comments.
McGuireWoods LLP
NEC Corporation
Pascal Leslie
Phan Hanh
LandOfFree
Wavelength division multiplexing system, wavelength division... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Wavelength division multiplexing system, wavelength division..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Wavelength division multiplexing system, wavelength division... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2559953