CONCATENATED OPTICAL SPECTRUM TRANSMISSION SYSTEMS AND METHODS

• US 20120219293A1
• Filed: 08/26/2011
• Published: 08/30/2012
• Est. Priority Date: 08/26/2010
• Status: Active Grant

• Current Assignee: Ciena Corporation
• Original Assignee: Ciena Corporation
• Inventors: Boertjes, David, Belanger, Michel
• Granted Patent: US 9,197,354 B2
• Time in Patent Office: Days
• US Class Current: 398/48
• CPC Class Codes: H04J 14/0204 Broadcast and select arrangements, e.g. with an optical splitter at the input before adding or dropping
• CPC Class Codes: H04J 14/0206 Express channels arrangements
• CPC Class Codes: H04J 14/0212 using optical switches or wavelength selective switches [WSS]
• CPC Class Codes: H04J 14/0213 Groups of channels or wave bands arrangements
• CPC Class Codes: H04J 14/0221 Power control, e.g. to keep the total optical power constant
• CPC Class Codes: H04J 14/0257 Wavelength assignment algorithms
• CPC Class Codes: H04Q 11/0066 Provisions for optical burst or packet networks
• CPC Class Codes: H04Q 2011/0016 using wavelength multiplexing or demultiplexing
• CPC Class Codes: H04Q 2011/0086 Network resource allocation, dimensioning or optimisation

Abstract

The present disclosure relates to concatenated optical spectrum transmission systems and methods that allocate optical spectrum of groups of channels to reduce or eliminate deadbands or guardbands (i.e., unused optical spectrum) between channels. The concatenated optical spectrum transmission systems and methods include various techniques for using optical spectrum such as over the C-band or any other frequency bands. In particular, the concatenated optical spectrum transmission systems and methods provide a balance between fixed channel systems such as provided for by the International Telecommunication Union (ITU) and a more flexible system enabled by coherent optical detection. In an exemplary embodiment, the concatenated optical spectrum transmission systems and methods may utilize a Wavelength Selective Switch (WSS) and a plurality of moderate Common Mode Rejection Ratio (CMRR) coherent receivers in combination to achieve a concatenated optical spectrum.

Claims

1. An optical network, comprising:

a first network element;

a second network element communicatively coupled to the first network element by a first optical fiber;

a first plurality of optical channels over the first optical fiber; and

a second plurality of optical channels over the first optical fiber;

wherein each of the first plurality of optical channels are located on an optical spectrum with substantially no spectrum between adjacent channels, and wherein each of the second plurality of optical channels are located on the optical spectrum with substantially no spectrum between adjacent channels.

2. The optical network of claim 1, wherein a guardband is defined on the optical spectrum between one end of the first plurality of optical channels and one end of the second plurality of optical channels.

3. The optical network of claim 2, further comprising:

a first flexible spectrum wavelength selective switch at the second network element, the first flexible spectrum wavelength selective switch configured to drop the first plurality of optical channels.

4. The optical network of claim 3, wherein the guardband is spectrally defined based on a roll-off associated with the first flexible spectrum wavelength selective switch.

5. The optical network of claim 3, further comprising at the second network element:

a first power splitter coupled to a drop port of the first flexible spectrum wavelength selective switch; and

a first plurality of Common Mode Rejection Ratio (CMRR) coherent optical receivers coupled to the power splitter, wherein each of the first plurality of CMRR coherent optical receivers receives each of the first plurality of optical channels and selectively receives one of the first plurality of optical channels.

6. The optical network of claim 3, wherein the first flexible spectrum wavelength selective switch comprises a continuous spectral response on adjacent actuated portions of the optical spectrum when pointed to the same port.

7. The optical network of claim 3, further comprising:

a third network element communicatively coupled to the second network element by a second optical fiber;

wherein the second plurality of optical channels is communicated over the second optical fiber and the first optical fiber.

8. The optical network of claim 7, further comprising:

a second flexible spectrum wavelength selective switch at the third network element, the second flexible spectrum wavelength selective switch configured to drop the second plurality of optical channels.

9. The optical network of claim 8, further comprising at the third network element:

a second power splitter coupled to a drop port of the second flexible spectrum wavelength selective switch; and

a second plurality of Common Mode Rejection Ratio (CMRR) coherent optical receivers coupled to the power splitter, wherein each of the second plurality of CMRR coherent optical receivers receives each of the second plurality of optical channels and selectively receives one of the second plurality of optical channels.

10. The optical network of claim 1, further comprising:

a plurality of bins defined on the optical spectrum, wherein each of the first plurality of optical channels and each of the second plurality of optical channels are assigned to one or more of the plurality of bins.

11. The optical network of claim 10, wherein at least two of the first plurality of optical channels comprise a different baud rate.

12. An optical system, comprising:

a flexible spectrum wavelength selective switch receiving a wavelength division multiplexed (WDM) signal and comprising at least one drop port configured to receive a first group of optical channels from the WDM signal with adjacent channels spectrally spaced substantially next to one another;

a power splitter coupled to the at least one drop port; and

a plurality of Common Mode Rejection Ratio (CMRR) coherent optical receivers coupled to the power splitter, wherein each of the CMRR coherent optical receivers receives each of the first group of optical channels and selectively receives one of the first group of optical channels.

13. The optical system of claim 12, wherein the flexible spectrum wavelength selective switch comprises a continuous spectral response on adjacent actuated portions of an optical spectrum when pointed to the at least one drop port.

14. The optical system of claim 12, wherein the flexible spectrum wavelength selective switch further comprises at least one express port configured to receive a second group of optical channels from the WDM signal, wherein an optical spectrum of the WDM signal comprises a guardband between the first group of optical channels and the second group of optical channels.

15. The optical system of claim 12, wherein the guardband is spectrally defined based on a roll-off associated with the flexible spectrum wavelength selective switch.

16. A method, comprising:

defining a plurality of bins on an optical spectrum associated with an optical fiber;

dropping a first optical signal to a first coherent optical receiver, wherein the first optical signal uses one or more bins of the plurality of bins; and

dropping a second optical signal to a second coherent optical receiver, wherein the second optical signal uses one or more of adjacent bins to the one or more bins used by the first optical signal.

17. The method of claim 16, further comprising:

defining guardbands in one or more of the plurality of bins, wherein the guardbands are spectrally defined based on a roll-off associated with a flexible spectrum wavelength selective switch.

18. The method of claim 16, wherein a number of bins for each of the first optical signal and the second optical signal is based on a format and baud rate associated therewith.

19. The method of claim 16, further comprising:

utilizing a management system to provision the first optical signal in the one or more bins.