Optical waveguides – With optical coupler – Switch
Reexamination Certificate
1999-01-19
2001-06-19
Bovernick, Rodney (Department: 2874)
Optical waveguides
With optical coupler
Switch
C385S024000, C359S199200
Reexamination Certificate
active
06249620
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a branching unit for an underwater optical communications system which carries wavelength division multiplexed (WDM) signals.
BACKGROUND TO THE INVENTION
Current branching unit designs for all WDM submarine communications systems use optical gratings as filters which only add or drop specific wavelengths and so do not allow wavelength or capacity reconfiguration between the trunk and the spur. In particular, it is not possible to disconnect a signal channel from the spur or increase the capacity of the spur by the addition of further channels.
SUMMARY OF THE INVENTION
According to a first aspect of the present invention, a branching unit for an underwater optical communications system comprises an optical switch and an optical multiplexer, the optical multiplexer having a number of loop-back optical paths which pass through the optical switch, wherein the optical switch is reconfigurable by changing the state of the optical switch so that individual channels of a multichannel optical signal received at a trunk input of the branching unit can be selectively coupled to a spur output and optical channels of a signal received at a spur input of the branching unit can be selectively coupled to a trunk output.
Preferably, the branching unit further comprises a demultiplexer in a spur input path coupled to the optical switch for demultiplexing an optical signal from the spur input and directing individual channels to a respective input port of the optical switch.
Preferably, the branching unit further comprises a multiplexer in a spur output path coupled to the optical switch for combining individual channels from respective output ports of the optical switch and coupling the resultant multiplexed optical signal to the spur output.
Preferably, for a communications system which can carry an n-channel WDM optical signal, the optical switch is a 2nx2n optical switch. Preferably, the optical multiplexer comprises an arrayed-waveguide multiplexer.
According to a second aspect of the present invention, a communications system comprises a number of branching units in accordance with the first aspect of the present invention.
REFERENCES:
patent: 5414548 (1995-05-01), Tachikawa et al.
patent: 5612805 (1997-03-01), Fevrier et al.
patent: 5771112 (1998-06-01), Hamel et al.
patent: 0 666 485 A1 (1995-08-01), None
patent: 0 699 927 A1 (1996-03-01), None
patent: 0 720 408 A2 (1996-07-01), None
patent: 007200408 A1 (1996-07-01), None
patent: 0 750 409 A1 (1996-12-01), None
patent: WO 97/06617 (1997-02-01), None
Simeonidou, D. et al.; “Submerged WDM Network Implementation Using All Optical Wavelength Routers” WDM Technology and Applications (Digest No. 1997/036), IEE Colloquium on, 1997 pp. 5/1-5/5.*
Ishida, O. et al.: “Multichannel Frequency-Selective Switch Employing an Arrayed-Waveguide Grating Multiplexer with Fold-Back Optical Paths” IEEE Photonics Technology Letters, vol. 6, No. 10, Oct. 1, 1994, pp. 1219-1221, XP000476947.
Tachikawa Y. et al.: “Arrayed-Waveguide Grating Multiplexer with Loop-Back Optical Paths and Its Applications” Journal of Lightwave Technology, vol. 14, No. 6, Jun. 1, 1996, pp. 977-984, XP000598501.
Long Christina
Simeonidou Dimitra
Alcatel
Bovernick Rodney
Song Sarah N.
Sughrue Mion Zinn Macpeak & Seas, PLLC
LandOfFree
Reconfigurable branching unit for a submarine communications... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Reconfigurable branching unit for a submarine communications..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Reconfigurable branching unit for a submarine communications... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2495745