Orthogonally-Combining Wavelength Selective Switch Multiplexer and Systems and Methods Using Same

• US 20120087657A1
• Filed: 10/12/2010
• Published: 04/12/2012
• Est. Priority Date: 10/12/2010
• Status: Active Grant

• Current Assignee: Tyco Electronics Subsea Communications LLC (TE Connectivity Ltd. (United Kingdom))
• Original Assignee: Tyco Electronics Subsea Communications LLC (TE Connectivity Ltd. (United Kingdom))
• Inventors: Jander, Ralph Brian, Jiang, Yan
• Granted Patent: US 8,731,402 B2
• Time in Patent Office: Days
• US Class Current: 398/48
• CPC Class Codes: H04J 14/02 Wavelength-division multiplex systems
• CPC Class Codes: H04J 14/0212 using optical switches or wavelength selective switches [WSS]
• CPC Class Codes: H04J 14/06 Polarisation multiplex systems
• CPC Class Codes: H04Q 11/0005 Switch and router aspects
• CPC Class Codes: H04Q 2011/0016 using wavelength multiplexing or demultiplexing
• CPC Class Codes: H04Q 2011/0049 Crosstalk reduction; Noise; Power budget

Abstract

In general, a wavelength division multiplexed (WDM) communication system may use wavelength selective switching to simultaneously pre-filter and combine groups of channel wavelengths with orthogonal polarizations to provide a pre-filtered, pair-wise orthogonal aggregate WDM optical signal. An orthogonally-combining wavelength selective switch (WSS) multiplexer may route channel wavelengths individually from different sets of channels to a common output. The orthogonally-combining WSS multiplexer may also provide substantially orthogonal polarizations for the wavelengths in the different sets of channels. The different sets of channels may include odd channels and even channels.

Claims

1. An orthogonally-combining wavelength selective switch (WSS) multiplexer comprising:

first and second optical input ports configured to receive first and second sets of multiplexed wavelengths;

first and second wavelength demultiplexers configured to demultiplex the first and second sets of multiplexed wavelengths, respectively;

a switch fabric configured to selectively route wavelengths demultiplexed from the first and second sets of wavelengths;

polarization optics configured to provide wavelengths in the first set of wavelengths with a first polarization and wavelengths in the second set of wavelengths with a second polarization, the first and second polarizations being substantially orthogonal;

a wavelength multiplexer configured to multiplex routed wavelengths with the first and second polarizations to produce pre-filtered, pair-wise orthogonal aggregate channel wavelengths; and

a combined channel optical output port configured to output the pair-wise orthogonal aggregate channel wavelengths.

2. The orthogonally-combining WSS multiplexer according to claim 1, wherein the first set of multiplexed wavelengths include odd channel wavelengths and the second set of multiplexed wavelengths include even channel wavelengths.

3. The orthogonally-combining WSS multiplexer according to claim 1, wherein the first optical input port and the second optical input port include fiber collimators coupled to polarization maintaining (PM) input fibers.

4. The orthogonally-combining WSS multiplexer according to claim 3 further comprising first and second input polarizers configured to increase a polarization extinction ratio of the first set of wavelengths and the second set of wavelengths, respectively.

5. The orthogonally-combining WSS multiplexer according to claim 1, further comprising a plurality of variable optical attenuators configured to adjust a power of the channel wavelengths, respectively, being routed by the switch fabric.

6. The orthogonally-combining WSS multiplexer according to claim 1, wherein the combined channel optical output includes a fiber collimator coupled to a PM output fiber.

7. The orthogonally-combining WSS multiplexer according to claim 1, wherein an angle between the first polarization and the second polarization is within a range of 90±

7 degrees.

8. The orthogonally-combining WSS multiplexer according to claim 1, wherein the polarization optics are located after the switch fabric.

9. The orthogonally-combining WSS multiplexer according to claim 1, wherein the polarization optics are configured to translate the polarization of the channel wavelengths in either the first set of wavelengths or the second set of wavelengths by about 90 degrees.

10. The orthogonally-combining WSS multiplexer according to claim 1, wherein the polarization optics are configured to translate the polarization of the channel wavelengths in either the first set of wavelengths or the second set of wavelengths such that the first and second polarizations are substantially orthogonal or substantially parallel.

11. An optical communication system comprising:

a transmitting terminal configured to transmit a wavelength division multiplexed (WDM) signal on a plurality of optical channels including a first set of channels and a second set of channels, the transmitting terminal comprising an orthogonally-combining wavelength selective switch (WSS) multiplexer configured to use wavelength selective switching to simultaneously pre-filter and combine a first set of channel wavelengths with a first polarization and a second set of channel wavelengths with a second polarization to produce a pre-filtered, pair-wise orthogonal aggregate optical signal, the first and second polarizations being substantially orthogonal;

a receiving terminal configured to receive the pair-wise orthogonal WDM aggregate optical signal on the plurality of optical channels and configured to separate the WDM aggregate optical signal into separate optical signals at the channel wavelengths; and

an optical transmission path coupling the transmitting terminal and the receiving terminal.

12. The optical communications system according to claim 11, wherein the first set of channel wavelengths include odd channel wavelengths associated with odd channels and the second set of channel wavelengths include even channel wavelengths associated with even channels.

13. The optical communication system according to claim 12, wherein the transmitting terminal further comprises:

a plurality of odd channel transmitters configured to modulate data on the odd channel wavelengths to produce optical signals on the odd channels;

an odd channel wavelength multiplexer configured to combine the optical signals at the odd channel wavelengths to produce an aggregate odd channel optical signal;

a plurality of even channel transmitters configured to modulate data on the even channel wavelengths to produce optical signals on the even channels; and

an even channel wavelength multiplexer configured to combine the optical signals at the even channel wavelengths to produce an aggregate even channel optical signal.

14. The optical communication system according to claim 13 wherein the odd channel wavelength multiplexer includes an n×

1 polarization maintaining WSS, and wherein the even channel wavelength multiplexer includes an n×

1 polarization maintaining WSS.

15. The optical communication system according to claim 13, wherein the receiving terminal further comprises:

a deinterleaver configured to separate the WDM signal into the aggregate odd channel signal including the odd channel wavelengths and the aggregate even channel signal including the even channel wavelengths;

an odd channel wavelength demultiplexer configured to separate the aggregate odd channel signal into separate optical signals at the respective odd channel wavelengths;

an even channel wavelength demultiplexer configured to separate the aggregate even channel signal into separate optical signals at the respective even channel wavelengths;

a plurality of odd channel receivers configured to receive and demodulate respective optical signals at the odd channel wavelengths; and

a plurality of even channel receivers configured to receive and demodulate respective optical signals at the even channel wavelengths.

16. The optical communication system according to claim 15 wherein the deinterleaver includes a 1×

2 WSS deinterleaver.

17. The optical communication system according to claim 15 wherein the odd channel wavelength demultiplexer includes a 1×

n WSS, and wherein the even channel wavelength demultiplexer includes a 1×

n WSS.

18. The optical communication system according to claim 11 wherein the orthogonally-combining WSS multiplexer comprises:

first and second optical input ports configured to receive first and second sets of multiplexed wavelengths;

first and second wavelength demultiplexers configured to demultiplex the first and second sets of channel wavelengths, respectively;

a switch fabric configured to selectively route wavelengths demultiplexed from the first and second sets of channel wavelengths;

polarization optics configured to provide wavelengths in the first set of wavelengths with the first polarization and wavelengths in the second set of wavelengths with the second polarization;

a wavelength multiplexer configured to multiplex routed wavelengths with the first and second polarizations to produce the pre-filtered, pair-wise orthogonal aggregate optical signal; and

a combined channel optical output port configured to output the pre-filtered, pair-wise orthogonal aggregate optical signal.

19. The optical communication system according to claim 11 wherein the transmitting terminal further comprises:

a first set of channel transmitters configured to modulate data on the first set of channel wavelengths to produce PM optical signals on the first set of channels;

a second set of channel transmitters configured to modulate data on the second set of channel wavelengths to produce PM optical signals on the second set of channels; and

wherein the WSS multiplexer comprises;

a first set of PM channel input ports configured to receive the first set of channel wavelengths respectively;

a second set of PM channel input ports configured to receive the second set of channel wavelengths respectively;

a switch fabric configured to selectively route wavelengths from the first and second sets of channel wavelengths;

polarization optics configured to provide wavelengths in the first set of wavelengths with the first polarization and wavelengths in the second set of wavelengths with the second polarization;

a wavelength multiplexer configured to multiplex routed wavelengths with the first and second polarizations to produce the pre-filtered, pair-wise orthogonal aggregate optical signal; and

a combined channel optical output port configured to output the pre-filtered, pair-wise orthogonal aggregate optical signal.

20. Line terminating equipment comprising:

a plurality of odd channel transponders configured to transmit and receive optical signals modulated on odd channel wavelengths;

a plurality of even channel transponders configured to transmit and receive optical signals modulated on even channel wavelengths;

at least one odd channel wavelength multiplexer configured to combine the optical signals modulated on the odd channel wavelengths after the odd channel transponders to produce an aggregate odd channel transmit optical signal;

at least one odd channel wavelength demultiplexer configured to separate received optical signals modulated on the odd channel wavelengths before the odd channel transponders;

at least one even channel wavelength multiplexer configured to combine the optical signals modulated on the even channel wavelengths after the even channel transponders to produce an aggregate even channel transmit optical signal;

at least one even channel wavelength demultiplexer configured to separate received optical signals modulated on the even channel wavelengths before the even channel transponders; and

an orthogonally-combining WSS multiplexer configured to use wavelength selective switching to simultaneously pre-filter and combine the odd channel wavelengths from the aggregate odd channel optical signal with a first polarization and the even channel wavelengths from the aggregate even channel optical signal with a second polarization to produce a pre-filtered, pair-wise orthogonal aggregate transmit optical signal, the second polarization being substantially orthogonal to the first polarization.

21. The line terminating equipment according to claim 20, wherein the orthogonally-combining WSS multiplexer comprises:

first and second optical input ports configured to receive odd channel wavelengths and the even channel wavelengths, respectively;

first and second wavelength demultiplexers configured to demultiplex the odd channel wavelengths and the even channel wavelengths, respectively;

a switch fabric configured to selectively route wavelengths demultiplexed from the odd channel wavelengths and the even channel wavelengths;

polarization optics configured to provide odd channel wavelengths with the first polarization and even channel wavelengths with the second polarization;

a wavelength multiplexer configured to multiplex routed wavelengths with the first and second polarizations to produce the pre-filtered, pair-wise orthogonal aggregate optical signal; and

a combined channel optical output port configured to output the pre-filtered, pair-wise orthogonal aggregate optical signal.

22. The line terminating equipment according to claim 21, wherein the orthogonally-combining WSS multiplexer further comprises a plurality of variable optical attenuators configured to adjust a power of the channel wavelengths, respectively, being routed by the switch fabric.

23. The line terminating equipment according to claim 20, wherein the odd channel wavelength multiplexer and the even channel wavelength multiplexer are coupled to the orthogonally-combining interleaving filter multiplexer with polarization maintaining (PM) input fibers.

24. An optical transmission method comprising:

modulating a plurality of data streams on a first set of channel wavelengths and on a second set of channel wavelengths, respectively, to produce optical signals on respective first and second sets of channels;

providing the optical signals on the first set of channels with a first polarization;

providing the optical signals on the second set of channels with a second polarization substantially orthogonal to the first polarization; and

simultaneously pre-filtering and combining the optical signals with the first polarization and the optical signals with the second polarization using wavelength selective switching to produce a pre-filtered, pair-wise orthogonal aggregate optical signal.

25. The optical transmission method according to claim 24, wherein the first set of channel wavelengths include odd channel wavelengths associated with odd channels and the second set of channel wavelengths include even channel wavelengths associated with even channels.

26. The optical transmission method according to claim 24 further comprising:

combining the optical signals on the first set of channels onto a single PM optical path;

combining the optical signals on the second set of channels onto a single PM optical path; and

combining the optical signals on the first and second sets of channels with a polarization maintaining beamsplitter.

27. The optical transmission method according to claim 26 wherein the optical signals on the first set of channels are combined with a first n×

1 polarization maintaining WSS, and wherein the optical signals on the second set of channels are combined with a second n×

1 polarization maintaining WSS.

28. The optical transmission method according to claim 24 further comprising:

providing the optical signals on the first set of channels to a first set of inputs to a 2n×

1 WSS multiplexer;

providing the optical signals on the second set of channels to a second set of inputs to the 2n×

1 WSS multiplexer; and

wherein the 2n×

1 WSS multiplexer pre-filters and combines the optical signals with the first and second polarizations to produce the pre-filtered, pair-wise orthogonal aggregate optical signal.

29. The optical transmission method according to claim 24, wherein the pre-filtered, pair-wise orthogonal aggregate optical signal has a spectral efficiency of 0.6 Bit/Hz or 0.8 Bit/Hz.

30. The optical transmission method according to claim 24, wherein the pre-filtered, pair-wise orthogonal aggregate optical signal has a channel spacing of about 33 GHz or 25 GHz.