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Plastic Optical Sub-assembly

IP.com Disclosure Number: IPCOM000122615D
Original Publication Date: 1991-Dec-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 1 page(s) / 36K

Publishing Venue

IBM

Related People

Blanks, SR: AUTHOR [+5]

Abstract

Optical Subassemblies (OSAs) present the greatest cost reduction opportunity in transceiver module design. Typically both transmitters (TOSAs) and receivers (ROSAs) are constructed from upwards of twelve precision stainless and ceramic parts that require several press fit and weld operations. The final construction operation is usually an active alignment to align the laser or LED to the fiber in the TOSA or the diode to the fiber in the ROSA. This invention uses the less demanding tolerances of multimode (MM) technology to enable the use of a precision molded plastic OSA body. To achieve this one-piece body design, the receiver or transceiver can housing must have the lens built in (see the figure). This design also eliminates the expensive zirconia bore that is often used in current designs.

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Plastic Optical Sub-assembly

      Optical Subassemblies (OSAs) present the greatest cost
reduction opportunity in transceiver module design. Typically both
transmitters (TOSAs) and receivers (ROSAs) are constructed from
upwards of twelve precision stainless and ceramic parts that require
several press fit and weld operations.  The final construction
operation is usually an active alignment to align the laser or LED to
the fiber in the TOSA or the diode to the fiber in the ROSA.  This
invention uses the less demanding tolerances of multimode (MM)
technology to enable the use of a precision molded plastic OSA body.
To achieve this one-piece body design, the receiver or transceiver
can housing must have the lens built in (see the figure).  This
design also eliminates the expensive zirconia bore that is often used
in current designs.

      To avoid mechanical deformation of the bore by the ferrule
(usually zirconia), the bore must have a continuous taper, as shown
in the figure, and the plastic must have a modulus of > 2 million
psi.  To obtain acceptable coupled power repeatability in plugging
the ferrule into the bore, the bore diameter must be controlled to
2.5u.  Initial results indicate that this precision is possible
with precise injection molding procedures.