Faraday cage and ceramic walls for shielding EMI

• US 20030159844A1
• Filed: 02/27/2002
• Published: 08/28/2003
• Est. Priority Date: 02/27/2002
• Status: Active Grant

• Current Assignee: Lumentum Operations, LLC (Lumentum Holdings Inc.)
• Original Assignee: Optronx Inc.
• Inventors: Craig, Eric A., Wolf, Robert K., Young, Craig A.
• Granted Patent: US 6,653,557 B2
• Time in Patent Office: Days
• US Class Current: 174/35R
• CPC Class Codes: G02B 6/4201 Packages, e.g. shape, construction, internal or external details
• CPC Class Codes: G02B 6/4208 using non-reciprocal elements or birefringent plates, i.e. quasi-isolators optical isolators per se G02F1/093, G02F1/0955
• CPC Class Codes: G02B 6/4214 the intermediate optical element having redirecting reflective means, e.g. mirrors, prisms for deflecting the radiation from horizontal to down- or upward direction toward a device G02B6/4246 takes precedence
• CPC Class Codes: G02B 6/4246 Bidirectionally operating package structures
• CPC Class Codes: G02B 6/4257 having a supporting carrier or a mounting substrate or a mounting plate G02B6/3648 takes precedence
• CPC Class Codes: G02B 6/4265 of the Butterfly or dual inline package [DIP] type
• CPC Class Codes: G02B 6/4266 Thermal aspects, temperature control or temperature monitoring thermal aspect of electrical circuits H05K7/20, H05K5/0213, temperature control in general G05D23/19
• CPC Class Codes: G02B 6/4267 Reduction of thermal stress, e.g. by selecting thermal coefficient of materials
• CPC Class Codes: G02B 6/4269 with heat sinks or radiation fins
• CPC Class Codes: G02B 6/4277 Protection against electromagnetic interference [EMI], e.g. shielding means shielding of electric apparatus H05K9/00, of instruments G12B17/00
• CPC Class Codes: G02B 6/4278 related to pluggable or demountable opto-electronic or electronic elements
• CPC Class Codes: H05K 9/0058 specially adapted for optoelectronic applications

Abstract

A Faraday cage enclosing an optical device extends between a metalized plate and an upper enclosure. The upper enclosure is vertically spaced from the metalized plate. The Faraday cage includes one or more ceramic wall portions that extend from the metalized plate to the upper enclosure and limit the passage of EMI through the ceramic wall portions. The ceramic wall portions include a plurality of laminated ceramic layers, each one of the laminated ceramic layers extending substantially parallel to the metalized plate, and a plurality of vias extending substantially perpendicular to the metalized plate through the laminated ceramic layers, each one of the plurality of vias extending substantially from the metalized plate to the upper enclosure. The plurality of vias are configured to form a pattern that limits the passage of EMI through the vias, wherein the metalized plate, the upper enclosure, and the ceramic wall portions define a Faraday cage that surrounds the optical device.

Claims

1. A Faraday cage to enclose an optical device, the Faraday cage extending between a metalized plate and an upper enclosure, the upper enclosure is vertically spaced from the metalized plate, the Faraday cage limits the passage of Electromagnetic Interference (EMI), the Faraday cage comprising:

one or more ceramic wall portions that extend from the metalized plate to the upper enclosure and limit the passage of EMI through the ceramic wall portions, the ceramic wall portions including;

a plurality of laminated ceramic layers, each one of the laminated ceramic layers extends substantially parallel to the metalized plate, and

a plurality of vias extending substantially perpendicular to the metalized plate through the laminated ceramic layers, each one of the plurality of vias extends substantially from the metalized plate to the upper enclosure, the plurality of vias are configured to form a pattern that limits said passage of EMI through the vias, wherein said metalized plate, said upper enclosure, and said one or more ceramic wall portions define a Faraday cage that surrounds said optical device.

2. The Faraday cage of claim 1, further including a metal backbone.

3. The Faraday cage of claim 2, wherein the optical fiber cable extends through the metal backbone.

4. The Faraday cage of claim 1, wherein the metalized plate, the upper enclosure, and the one or more ceramic wall portions are each formed as distinct components.

5. The Faraday cage of claim 1, wherein adjacent ones of said vias are spaced from each other by a distance of less than a quarter wavelength (λ

/4) of the highest operating frequency component requiring attenuation.

6. The Faraday cage of claim 1, wherein the optical device is an optical receiver, and the Faraday cage is configured to limit the transmission of EMI from outside of the Faraday cage to within the Faraday cage.

7. The Faraday cage of claim 1, wherein the optical device is an optical transmitter, and the Faraday cage is configured to limit the transmission of EMI from within the Faraday cage to outside of the Faraday cage.

8. The Faraday cage of claim 1, wherein each one of the vias is plated with metal and filled with air.

9. The Faraday cage of claim 1, wherein each one of the vias is filled with metal.

10. The Faraday cage of claim 1, wherein each one of the laminated ceramic layers are cofired.

11. A ceramic wall portion positioned relative to an optical device that limits the passage of EMI through the ceramic wall portion, comprising:

a plurality of substantially parallel laminated ceramic layers; and

a plurality of vias extending substantially perpendicular to the plurality of laminated ceramic layers, the plurality of vias extend through the laminated ceramic and are configured to form a pattern that limits said passage of EMI through the vias, wherein said ceramic wall portion partially defines a Faraday cage that surrounds said optical device.

12. The ceramic wall portion of claim 11, wherein adjacent ones of said vias are spaced from each other by a distance of less than a quarter wavelength (λ

/4) of the highest operating frequency component requiring attenuation.

13. The ceramic wall portion of claim 11, wherein the optical device is an optical receiver, and wherein the ceramic wall portion partially defines a Faraday cage that is configured to limit the transmission of EMI from outside of the Faraday cage to within the Faraday cage.

14. The ceramic wall portion of claim 11, wherein the optical device is an optical transmitter, and wherein the ceramic wall portion partially defines a Faraday cage that is configured to limit the transmission of EMI from within the Faraday cage to outside of the Faraday cage.

15. The ceramic wall portion of claim 11, wherein each one of the plurality of vias is plated with metal and filled with air.

16. The ceramic wall portion of claim 11, wherein each one of the plurality of vias is filled with metal.

17. The ceramic wall portion of claim 11, wherein each one of the laminated ceramic layers is cofired.

18. A method of manufacturing a ceramic wall portion that is configured to act as a portion of a Faraday cage, the method comprising:

a) providing a ceramic layer;

b) depositing a metalization pattern on an upper surface of the ceramic layer, wherein the metalization pattern forms an electric lead interconnect/electric trace; and

c) cofiring the ceramic layer with the deposited metalization pattern.

19. The method of claim 18, further comprising repeating steps a), b), and c) to form a desired number of ceramic layers having metalization patterns formed therebetween to form the ceramic wall portion.

20. The method of claim 19, wherein a plurality of substantially parallel vias extend through the cofired ceramic layer.

21. The method of claim 20, wherein the vias are vertically oriented.

22. The method of claim 20, wherein the vias are horizontally oriented.

23. The method of claim 19, further comprising filling at least some of the plurality of substantially parallel vias with a metal.