Optical packet tray router
View Patent ↗An optical packet tray router is disclosed that manipulates a signal wavelength as the fundamental control mechanism. The disclosed optical packet tray router aggregates one or more packets in a packet tray for transmission over a network. The header information associated with each packet is used to route each packet to the appropriate destination channel and to make timing decisions. A wavelength server generates optical control wavelengths in response to the timing decisions. A generated optical control wavelength is used to adjust the wavelength of a given packet tray and thereby introduce a wavelength selective delay to the packet tray to align packet trays or to shift one or more packet trays to avoid a collision. The wavelength of the packet tray is converted to a control wavelength corresponding to an identified delay, irrespective of the initial channel upon which the packet tray was received. At the output stage of the packet tray router, the packet tray wavelength can be converted to any desired output channel wavelength.
1. A method performed by a router for routing an optical signal, comprising:
receiving a packet tray including a tray header and a plurality of packets, said packet tray having an associated initial wavelength; and
adjusting said associated initial wavelength of said packet tray to control the routing of said packet tray based on a label in said tray header of said packet tray through a plurality of stages of said router, wherein said adjusting step further comprises the step of shifting one or more packet trays prior to a switching of said one or more packet trays to avoid a collision on an output channel.
2. The method of claim 1 , wherein a payload associated with said packet tray is processed only as an optical signal.
3. The method of claim 1 , wherein header information associated with said packet tray is processed as an electrical signal.
4. The method of claim 1 , wherein header information associated with said packet tray is processed as an optical signal.
5. The method of claim 1 , wherein header information associated with said packet tray is processed as a hybrid of optical and electrical signals.
6. The method of claim 1 , further comprising the step of switching said packet tray received on an input channel to an appropriate output channel based on associated header information.
7. The method of claim 1 , wherein said packet tray is multiplexed in a wavelength division multiplexed system to transmit said packet tray with a plurality of additional packet trays on a same channel.
8. The method of claim 1 , further comprising the step of restoring said packet tray.
9. The method of claim 1 , wherein said adjusting step further comprises the step of aligning each packet tray to a master clock-based start of packet tray temporal reference using a tunable optical delay.
10. The method of claim 1 , further comprising the step of updating header information of said packet tray to include routing information for a subsequent node.
11. The method of claim 10 , wherein said header information is updated in an optical domain.
12. An optical packet tray router, comprising:
a wavelength demultiplexer for separating a plurality of packet trays received on a same channel, wherein one or more of said packet trays include a plurality of packets;
a header section for extracting header information from a header portion of each packet tray and for processing said header information associated with each packet tray to route each packet tray to an appropriate destination channel and to make wavelength and timing decisions; and
a data section for processing said packet trays only in an optical domain, said data section introduces at least one wavelength selective delay to a packet tray based on said timing decisions.
13. The packet tray router of claim 12 , wherein said wavelength selective delay is based on a generated optical control wavelength that adjusts a wavelength of a given packet tray.
14. The packet tray router of claim 13 , wherein said generated optical control wavelength is generated by a wavelength server.
15. The packet tray router of claim 13 , wherein said generated optical control wavelength is applied to a multi-wavelength Bragg grating that shifts temporally a packet tray based on an optical control wavelength assigned to the packet tray.
16. The packet tray router of claim 13 , wherein said generated optical control wavelength is applied to a dispersive medium where the transmission time through the dispersive medium is a function of an optical control wavelength assigned to the packet tray.
17. The packet tray router of claim 12 , wherein said wavelength demultiplexer is embodied as a banded demultiplexer to permit wavelength banding.
18. The packet tray router of claim 12 , wherein said wavelength demultiplexer demultiplexes high rate data on a single wavelength in an OTDM system.
19. A wavelength server that generates a plurality of optical control wavelengths for a plurality of optical switching channels, comprising:
a broadband laser source to generate a laser source signal covering a wavelength range including said plurality of optical control wavelengths;
an optical gain stage for amplifying said laser source signal;
at least one lens that creates a parallel wave front in said laser source signal;
a tunable grating array, wherein each element in said tunable grating array simultaneously generates one of said plurality of optical control wavelengths, wherein said plurality of optical control wavelengths are used by a plurality of optical switching channels; and
a plurality of fibers coupled to said tunable grating array, each of said fibers carrying a corresponding one of said plurality optical control wavelengths.
20. The wavelength server of claim 19 , wherein each of said optical control wavelengths adjusts a wavelength of a packet tray to achieve a desired routing of an optical signal.
21. The wavelength server of claim 19 , wherein each of said optical control wavelengths adjusts a wavelength of a packet tray to introduce a wavelength selective delay.
22. The wavelength server of claim 19 , wherein said at least one lens is fabricated using a traditional optical bench approach.
23. The wavelength server of claim 19 , wherein said at least one lens is fabricated using a silicon optical bench approach.
24. The wavelength server of claim 19 , further comprising means for coupling said tunable grating array to a fiber bundle array.
25. A method for generating a plurality of optical control wavelengths for a plurality of optical switching channels, comprising:
generating a laser source signal covering a wavelength range including said plurality of optical control wavelengths;
amplifying said laser source signal;
creates a parallel wave front in said laser source signal;
applying said laser source to a tunable grating array, wherein each element in said tunable grating array simultaneously generates one of said plurality of optical control wavelengths, wherein said plurality of optical control wavelengths are used by a plurality of optical switching channels; and
coupling a plurality of fibers coupled to said tunable grating array, each of said fibers carrying a corresponding one of said plurality optical control wavelengths.
26. The method of claim 25 , wherein each of said optical control wavelengths adjusts a wavelength of a packet tray to achieve a desired routing of an optical signal.
27. The method of claim 25 , wherein each of said optical control wavelengths adjusts a wavelength of a packet tray to introduce a wavelength selective delay.
28. The method of claim 25 , wherein said parallel wave is created using at least one lens fabricated using a traditional optical bench approach.
29. The method of claim 25 , wherein said parallel wave is created using at least one lens fabricated using a silicon optical bench approach.
30. The method of claim 25 , further comprising the step of coupling said tunable grating array to a fiber bundle array.
31. A method for processing an optical signal in a multi-stage network node, comprising:
converting a wavelength of said optical signal to an optical control wavelength appropriate for a current stage using a tunable continuous wave light received over a fiber carrying only said wavelength from a wavelength server that simultaneously generates a plurality of optical control wavelengths for a plurality of optical switching channels;
processing said optical signal in an optical domain using a passive device; and
converting a wavelength of said optical signal to an optical control wavelength appropriate for a subsequent stage using a tunable continuous wave light received from said wavelength server.
32. The method of claim 31 , wherein said converting steps further comprise a restoration of said optical signal.
33. The method of claim 31 , wherein said processing step implements a switching function.
34. The method of claim 31 , wherein said processing step implements an alignment function.
35. The method of claim 31 , wherein said processing step implements a multiplexing function.
36. The method of claim 31 , wherein said processing step implements a delay function.
37. An optical signal processor in a multi-stage network node, comprising:
a wavelength converter for converting a wavelength of said optical signal to an optical control wavelength appropriate for a current stage using a tunable continuous wave light received over a fiber carrying only said wavelength from a wavelength server that simultaneously generates a plurality of optical control wavelengths for a plurality of optical switching channels;
a passive device for processing said optical signal in an optical domain; and
a wavelength converter for converting a wavelength of said optical signal to an optical control wavelength appropriate for a subsequent stage using a tunable continuous wave light received from said wavelength server.
38. The optical signal processor of claim 37 , wherein said wavelength converters are further configured to restore said optical signal.
39. The method of claim 37 , wherein said passive device implements a switching function.
40. The method of claim 37 , wherein said passive device implements an alignment function.
41. The method of claim 37 , wherein said passive device implements a multiplexing function.
42. The method of claim 37 , wherein said passive device implements a delay function.