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Optical Subassemblies Made Using Index Alignment Scheme

IP.com Disclosure Number: IPCOM000105124D
Original Publication Date: 1993-Jun-01
Included in the Prior Art Database: 2005-Mar-19
Document File: 2 page(s) / 49K

Publishing Venue

IBM

Related People

Bassous, E: AUTHOR [+8]

Abstract

The index-aligned, passive method of making optical submodules offers low cost, high data-rates, and reproducible coupling efficiency [*]. These submodules may be made using a silicon substrate which can incorporate structures related to driving the laser as well as those useful for monitoring and controlling the laser power. It is possible to fit such a submodule into a higher-level cylindrical-package geometry.

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Optical Subassemblies Made Using Index Alignment Scheme

      The index-aligned, passive method of making optical submodules
offers low cost, high data-rates, and reproducible coupling
efficiency [*].  These submodules may be made using a silicon
substrate which can incorporate structures related to driving the
laser as well as those useful for monitoring and controlling the
laser power.  It is possible to fit such a submodule into a
higher-level cylindrical-package geometry.

      A common Transmitter Optical Sub-Assembly (TOSA) consists of
laser in a cylindrical package, e.g., a TO can, which is provided
with a window so that the light can pass through the wall of the can
on its way to the fiber.  A lens, which is placed either inside or
outside the can, is often provided to focus the laser beam on the
fiber for improved coupling efficiency.

      Here, a laser-fiber submodule is prepared by the
Index-Alignment method, the short fiber stub is fed into a ferrule
and incorporated into a half-connector.  The ferrule is cut away to
provide a flat platform for the submodule.  The latter is bonded to
the flat on the ferrule, and the ferrule is fitted into a cylindrical
shell (TOSA body).  Electrical leads from the laser-fiber submodule
(flexible circuit carrier) pass through an end cap on the cylindrical
shell, thereby permitting connection to appropriate circuitry for
driving the laser and for pickup of the output of the monitor
photodiode.

      The T...