Optical switch fabric for data center interconnections

• US 9,551,836 B2
• Filed: 01/13/2015
• Issued: 01/24/2017
• Est. Priority Date: 04/25/2012
• Status: Active Grant

• Current Assignee: Ciena Corporation
• Original Assignee: Ciena Corporation
• Inventors: Frankel, Michael Y., Gazier, Michael, Berthold, Joseph
• Primary Examiner(s): Stahl, Mike
• Application Number:
  US14/595,241
• Publication Number:
  US 20150125112A1
• Time in Patent Office: 742 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: G02B 6/26 Optical coupling means G02B6/36, G02B6/42 take precedence
• CPC Class Codes: G02B 6/35 having switching means by changing the optical properties of the medium G02F1/00
• CPC Class Codes: H04B 10/271 Combination of different networks, e.g. star and ring configuration in the same network or two ring networks interconnected
• 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 14/0257 Wavelength assignment algorithms
• CPC Class Codes: H04Q 11/0001 using optical switching
• CPC Class Codes: H04Q 11/0005 Switch and router aspects
• CPC Class Codes: H04Q 2011/003 using switches based on microelectro-mechanical systems [MEMS]
• CPC Class Codes: H04Q 2011/0032 using static wavelength routers (e.g. arrayed waveguide grating router [AWGR] )

Abstract

An optical switch fabric includes horizontal optical waveguides including a first set and a second set, the first set is configured to receive a first plurality of wavelengths from the one or more external switches and the second set is configured to send a second plurality of wavelengths to the one or more external switches; wavelength-selective drop optical switches associated with the first set, wherein the wavelength-selective drop optical switches are each configured to drop a selected wavelength from a horizontal optical waveguide of the first set to an associated vertical optical waveguide of vertical optical waveguides; and controllable optical switches associated with the vertical optical waveguides, wherein the controllable optical switches are each configured to direct a selected wavelength from a vertical optical waveguide to a horizontal optical waveguide of the second set.

Claims

1. An optical switch fabric, comprising:

horizontal optical waveguides comprising a first set and a second set, the first set is configured to receive a first plurality of wavelengths from one or more external switches and the second set is configured to send a second plurality of wavelengths to the one or more external switches;

vertical optical waveguides;

wavelength-selective drop optical switches associated with the first set, wherein the wavelength-selective drop optical switches are each configured to drop a selected wavelength from a horizontal optical waveguide of the first set to an associated vertical optical waveguide of the vertical optical waveguides; and

controllable optical switches associated with the vertical optical waveguides, wherein the controllable optical switches are each configured to direct a selected wavelength from a vertical optical waveguide to a horizontal optical waveguide of the second set,

wherein the first set and the second set each have a quantity of C waveguides, C is an integer, and each of the first set receive L wavelengths, L is an integer, and wherein the first set and the second set have C×

L*(integer of (C/L)+1) crossings.

2. The optical switch fabric of claim 1, wherein one or more of the wavelength-selective drop optical switches and the controllable optical switches are dynamically reconfigurable.

3. The optical switch fabric of claim 1, wherein the optical switch fabric is rearrangeably non-blocking via a centralized controller coupled to the optical switch fabric.

4. The optical switch fabric of claim 1, wherein the one or more external switches are electrical switches.

5. The optical switch fabric of claim 1, wherein the horizontal optical waveguides and the vertical optical waveguides are coupled by a plurality of ring resonators comprising the wavelength-selective drop optical switches.

6. The optical switch fabric of claim 1, wherein the optical switch fabric is implemented on a silicon die.

7. The optical switch fabric of claim 1, wherein each of the wavelength-selective drop optical switches is a dynamic filter that directs one specific wavelength down to an associated vertical optical waveguide.

8. An optical switch system, comprising:

a waveguide grid comprising 2×

C horizontal waveguides with a first set of the 2×

C horizontal waveguides each configured to receive L wavelengths and C×

L*(integer of (C/L)+1)crossings with vertical waveguides, C and L are integers;

a drop optical switch at each intersection of the first set of the 2×

C horizontal waveguides and the vertical waveguides, the drop optical switch is configured to drop one of the L wavelengths; and

an add optical switch at each intersection of the vertical waveguides and a second set of the 2×

C horizontal waveguides, the add optical switch is configured to add a wavelength from the vertical waveguides to the second set of the 2×

C horizontal waveguides for output thereon.

9. The optical switch system of claim 8, wherein the L wavelengths are input from C rack switches in a data center on the first set of the 2×

C horizontal waveguides and output to the C rack switches on the second set of the 2×

C horizontal waveguides.

10. The optical switch system of claim 8, wherein the waveguide grid, the drop optical switch at each intersection, and the add optical switch at each intersection are formed on a silicon die.

11. The optical switch system of claim 8, wherein the drop optical switch at each intersection and the add optical switch at each intersection are constructed from a Silicon-based ring resonator structure.

12. The optical switch system of claim 8, wherein L is at least 40 and C is at least 40.

13. The optical switch system of claim 8, wherein the waveguide grid utilizes Silicon Nitride waveguides, and wherein the drop optical switch at each intersection and the add optical switch at each intersection are a polycrystalline Silicon ring.

14. A photonic die with an optical switch formed thereon, comprising:

horizontal waveguides comprising a first set of C waveguides configured to receive inputs from C switches and a second set of C waveguides configured to transmit outputs to the C switches, C being an integer;

vertical waveguides intersecting the first set and the second set of the horizontal waveguides;

a drop optical switch at each intersection of the first set with the vertical waveguides; and

an add optical switch at each intersection of the second set with the vertical waveguides;

wherein the inputs from the C switches are L wavelengths and a number of crossings between the vertical waveguides and the horizontal waveguides is C×

L*(integer of (C/L)+1).

15. The photonic die of claim 14, wherein the photonic die is a complementary metal oxide semiconductor (CMOS) integrated die.

16. The photonic die of claim 14, wherein the horizontal waveguides and the vertical waveguides utilize Silicon Nitride waveguides, and wherein the drop optical switch at each intersection and the add optical switch at each intersection are a polycrystalline Silicon ring.