Electromagnetic interference (EMI) waveguide device for use in a parallel optical communications module, and a method

1. An electromagnetic interference (EMI) waveguide (WG) device for use in a parallel optical communications module, the EMI WG device comprising:

a generally flat cover made of an electrically-conductive material, the cover having a mounting portion for mechanically coupling the cover to a metal housing of the parallel optical communications module;

a tube-like structure made of an electrically-conductive material, the tube-like structure having a first end that is mechanically coupled to the cover, the tube-like structure having an effective length, L, and an effective diagonal dimension, D, and wherein D is sufficiently large to accommodate at least one optical fiber ribbon cable to enable a portion of said at least one optical fiber ribbon cable to pass through an opening in the tube-like structure that is defined by interior surfaces of the tube-like structure, wherein the opening has the diagonal dimension, D, and wherein the cover and the tube-like structure provide EMI shielding for the parallel optical communications module when the EMI WG device is installed in the metal housing; and

an electrically-conductive gasket that wraps around at least a portion of the first end of the tube-like structure, the gasket being disposed to come into contact with a metal housing of the parallel optical communications module when the EMI WG device is installed in the parallel optical communications module to electrically ground the EMI WG device to the metal housing.

2. The EMI WG device of claim 1 , wherein the tube-like structure comprises an upper U-shaped portion and a lower U-shaped portion that are coupled together to form the tube-like structure.

3. The EMI WG device of claim 2 , wherein the effective diagonal dimension, D, is sufficiently large to accommodate at least two optical fiber ribbon cables to enable respective portions of the optical fiber ribbon cables to pass through the opening in the tube-like structure.

4. The EMI WG device of claim 3 , wherein each of the optical fiber ribbon cables includes a 1×N array of optical fibers, where N is a positive integer that is equal to or greater than two.

5. The EMI WG device of claim 4 , wherein N is equal to or greater than twelve.

6. The EMI WG device of claim 1 , wherein the cover and the upper and lower U-shaped portions of the EMI WG device comprise sheet metal.

7. The EMI WG device of claim 1 , wherein the gasket comprises an elastomeric material that is impregnated with an electrically conductive material to provide the gasket with elasticity and electrical conductivity characteristics.

8. The EMI WG device of claim 7 , wherein the gasket is U-shaped to comply with the U-shape of the lower U-shaped portion, and wherein the elasticity characteristic of the gasket ensures that the gasket snugly grips the first end of the lower U-shaped portion and is in continuous contact therewith.

9. The EMI WG device of claim 1 , wherein the effective length, L, is approximately 9.0 millimeters (mm).

10. The EMI WG device of claim 1 , wherein the diagonal dimension, D, is approximately 3.6 millimeters (mm).

11. The EMI WG device of claim 1 , wherein an aspect ratio of D/L is approximately 0.4.

12. The EMI WG device of claim 1 , wherein the optical fiber ribbon cable includes a 1×N array of optical fibers, where N is a positive integer that is equal to or greater than two, and wherein each optical fiber carries an optical data signal having a frequency that is equal to or greater than 5 Gigahertz (GHz).

13. The EMI WG device of claim 1 , wherein the optical fiber ribbon cable includes a 1×N array of optical fibers, where N is a positive integer that is equal to or greater than two, and wherein each optical fiber carries an optical data signal having a frequency that is equal to or greater than 10 Gigahertz (GHz).

14. A method for providing electromagnetic interference (EMI) shielding in a parallel optical communications module, the method comprising:

installing an electromagnetic interference (EMI) waveguide (WG) device in a metal housing of a parallel optical communications module, the EMI WG device comprising:

a generally flat cover made of an electrically-conductive material having a mounting portion that is mechanically coupled to the metal housing,

a tube-like structure made of an electrically-conductive material, the tube-like structure having a first end that is mechanically coupled to the cover, the tube-like structure having an effective length, L, and an effective diagonal dimension, D, and wherein D is sufficiently large to accommodate at least one optical fiber ribbon cable, wherein a portion of said at least one optical fiber ribbon cable passes through an opening in the tube-like structure that is defined by interior surfaces of the tube-like structure, wherein the opening has the diagonal dimension, D, and

an electrically-conductive gasket that wraps around at least a portion of the first end of the tube-like structure, the gasket is in contact with the metal housing and electrically grounds the EMI WG device to the metal housing.

15. The method of claim 14 , wherein the tube-like structure comprises an upper U-shaped portion and a lower U-shaped portion that are coupled together to form the tube-like structure.

16. The method of claim 15 , wherein the effective diagonal dimension, D, is sufficiently large to accommodate at least two optical fiber ribbon cables to enable respective portions of the optical fiber ribbon cables to pass through the opening in the tube-like structure.

17. The method of claim 16 , wherein each of the optical fiber ribbon cables includes a 1×N array of optical fibers, where N is a positive integer that is equal to or greater than two.

18. The method of claim 17 , wherein N is equal to or greater than twelve.

19. The method of claim 14 , wherein the cover and the upper and lower U-shaped portions of the EMI WG device comprise sheet metal.

20. The method of claim 14 , wherein the gasket comprises an elastomeric material that is impregnated with an electrically conductive material to provide the gasket with elasticity and electrical conductivity characteristics.

21. The method of claim 20 , wherein the gasket is U-shaped to comply with the U-shape of the lower U-shaped portion, and wherein the elasticity characteristic of the gasket ensures that the gasket snugly grips the first end of the lower U-shaped portion and is in continuous contact therewith.

22. The method of claim 14 , wherein the effective length, L, is approximately 9.0 millimeters (mm).

23. The method of claim 14 , wherein the diagonal dimension, D, is approximately 3.6 millimeters (mm).

24. The method of claim 14 , wherein an aspect ratio of D/L is approximately 0.4.

25. The method of claim 14 , wherein the optical fiber ribbon cable includes a 1×N array of optical fibers, where N is a positive integer that is equal to or greater than two, and wherein each optical fiber carries an optical data signal having a frequency that is equal to or greater than 5 Gigahertz (GHz).

26. The method of claim 14 , wherein the optical fiber ribbon cable includes a 1×N array of optical fibers, where N is a positive integer that is equal to or greater than two, and wherein each optical fiber carries an optical data signal having a frequency that is equal to or greater than 10 Gigahertz (GHz).