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Demountable Fiber to Waveguide Array Connector

IP.com Disclosure Number: IPCOM000109903D
Original Publication Date: 1992-Sep-01
Included in the Prior Art Database: 2005-Mar-24
Document File: 5 page(s) / 210K

Publishing Venue

IBM

Related People

Cina, MF: AUTHOR [+3]

Abstract

Disclosed is a demountable fiber to waveguide connector appropriate for both single and array connections. Optical alignment and mechanical support are achieved simultaneously through the use of physical registration features which are co-processed with the waveguide structures. This approach therefore eliminates the need for active alignment.

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This is the abbreviated version, containing approximately 42% of the total text.

Demountable Fiber to Waveguide Array Connector

       Disclosed is a demountable fiber to waveguide connector
appropriate for both single and array connections.  Optical alignment
and mechanical support are achieved simultaneously through the use of
physical registration features which are co-processed with the
waveguide structures.  This approach therefore eliminates the need
for active alignment.

      Most waveguide devices, single or array, are packaged with
fiber pigtails which are aligned and permanently bonded to the
waveguide substrate.  Pigtails are undesirable because they make the
package cumbersome to handle in manufacturing.  A similar situation
can exist for optoelectronic (O-E) modules using waveguides to
transmit optical signals between the O-E devices and the edge of a
module.  Here, the packaging of the module onto higher level packages
is unwieldy.  It is, therefore, desirable to have a pluggable optical
connector which can be connected to waveguides and removed multiple
times. The waveguides are the interface between the optical
components and the fiber-optic cable.

      The method described consists of a commercially available
optical array connector which is used for joining or splicing
fiber-optic cables.  By suitable modification, the connector can be
made to couple an array of fibers to an array of waveguides.  The
connector consists of two identical halves, or ferrules, which are
aligned to each other with steel pins and held together with spring
clips.  Using one ferrule of this connector with a modified set of
alignment pins, a demountable connector has been developed which
couples an array of fibers to an array of waveguides.  The connector
used here is the NTT- type MT (mechanical transfer) connector with up
to eight fibers on 250 micron centers (*).  Fig. 1 shows two
connector halves with alignment pins and spring clip.

      Substrates with waveguides have been fabricated that couple
light from a laser to the edge of the substrate and waveguides from
the edge of the substrate to a receiver chip.  Eight waveguides, 4
receiver and 4 transmitter, on 250-micron centers couple to eight
fibers mounted and polished in an MT ferrule.  Fig. 2 shows an array
connector with eight fibers mating to eight waveguides on a module.
The waveguide ends are lapped and polished to ensure optical quality
of the waveguide ends and to minimize the gap from the waveguide to
the fiber.  The alignment of the fiber array to the waveguides is
achieved through the use of modified alignment pins which are
attached to the substrate of the O-E module.  The alignment of the
pins to the waveguide array is provided by registration features
which are etched into the wave guide material.  The waveguides and
the pin alignment features are lithographically defined with the same
masking step giving precision placement of the pins.

      Two types of pin-alignment structures have been fabricated and
tested. ...