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PSEUDO ELECTRIC CONTACT BY WAVEGUIDE SLOTS FOR ELECTROMAGNETIC INTERFERENCE REDUCTION

IP.com Disclosure Number: IPCOM000217129D
Publication Date: 2012-May-03
Document File: 7 page(s) / 235K

Publishing Venue

The IP.com Prior Art Database

Related People

Xiaoxia Zhou: AUTHOR [+5]

Abstract

Optical cages generally contain a mid-section that is reserved for light emitting diodes (LEDs) that indicate a status of the transmit and receive data lines. The mid-section, also referred to as a “light-pipe” area, acts as a waveguide at high frequencies. Electromagnetic (EM) radiation caused by optical modules can easily couple into the light-pipe area and leak through openings or seams in front of the light-pipe area. Traditionally, optical cage vendors incorporate a metallic structure in the light-pipe area to try to reduce the EM interference (EMI) leakage. However, these techniques are dependent on having a good contact between the clip and the midsection. The solution described herein involves constructing a pseudo electric contact by using waveguide slots to reduce the EMI without requiring a perfect contact between the clip and midsection.

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PSEUDO ELECTRIC CONTACT BY WAVEGUIDE SLOTS FOR ELECTROMAGNETIC INTERFERENCE REDUCTION

AUTHORS: Xiaoxia Zhou Hongmei Fan

 Alpesh Bhobe Jinghan Yu Philippe Sochoux

CISCO SYSTEMS, INC.

                  ABSTRACT
Optical cages generally contain a mid-section that is reserved for light emitting

diodes (LEDs) that indicate a status of the transmit and receive data lines. The mid- section, also referred to as a "light-pipe" area, acts as a waveguide at high frequencies. Electromagnetic (EM) radiation caused by optical modules can easily couple into the light-pipe area and leak through openings or seams in front of the light-pipe area. Traditionally, optical cage vendors incorporate a metallic structure in the light-pipe area to try to reduce the EM interference (EMI) leakage. However, these techniques are dependent on having a good contact between the clip and the midsection. The solution described herein involves constructing a pseudo electric contact by using waveguide slots to reduce the EMI without requiring a perfect contact between the clip and midsection.

             DETAILED DESCRIPTION
A pseudo electric contact is provided to reduce electromagnetic interference

(EMI) generated by optical modules. The pseudo electric contact reduces EMI by using waveguide slots, which can be applied in a shielding enclosure design. For example, small form-factor pluggable (SFP) cages, vent holes and connectors may be used as a shielding design.

    Existing techniques are shown in FIG. 1. As shown, optical modules may be housed in metallic cages for EMI shielding. The shielding effect of these cages,

Copyright 2012 Cisco Systems, Inc. 1


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however, is very poor since EMI leakage may occur through the light-pipe area. As shown in FIG. 2, gaps may occur between the clip and the midsection of the cage.

    A solution to solve...