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Browse Prior Art Database

Fiber Optic Socket for Multi-chip Module

IP.com Disclosure Number: IPCOM000103729D
Original Publication Date: 1993-Jan-01
Included in the Prior Art Database: 2005-Mar-18
Document File: 3 page(s) / 97K

Publishing Venue

IBM

Related People

Overfield, RB: AUTHOR [+2]

Abstract

For high-speed circuit performance, the control of delay, crosstalk, coupled noise and EMI emissions is critical. The same parameters, called parasitics, impact the printed circuit-based packaging technology. The use of fiber optics provides a way to convert electrical signals to optical transmissions. This will reduce or eliminate these performance degrading factors since the use of printed circuits can be eliminated altogether [1]. The use of fiber optics also helps by providing increased bandwidth, reduced power dissipation and demountability.

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Fiber Optic Socket for Multi-chip Module

       For high-speed circuit performance, the control of delay,
crosstalk, coupled noise and EMI emissions is critical.  The same
parameters, called parasitics, impact the printed circuit-based
packaging technology.  The use of fiber optics provides a way to
convert electrical signals to optical transmissions.  This will
reduce or eliminate these performance degrading factors since the use
of printed circuits can be eliminated altogether [1].  The use of
fiber optics also helps by providing increased bandwidth, reduced
power dissipation and demountability.

      There are many z-axis interposer designs available for
demountable interconnections [2,3,4].  These designs are, however,
limited by the amount of information that can be carried per
input/output (I/O) pin.  Fiber optic based interconnections provide a
solution to this bottleneck.  Fig. 1 shows the disclosed concept.
Multi-chip module (MCM) carrier interfaces with an electrical-optical
converter module (EOM).  The top face of EOM has an array of pads to
match the MCM I/O pads at the bottom of the multi-chip carrier.
These interconnections are either soldered or demountable.

      The optical signals are transmitted through LEDs located at the
bottom of the EOM module.  The LEDs are then mated to fiber-optic
cables housed in a socket-type body.  The whole assembly, i.e., MCM,
EOM and socket body, can be mounted in a picture frame assembly to
provide MCM to MCM communication.  The picture frame body can also
act as a cold frame to dissipa...