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Optical Wave Guide Circuit for Multi-Axis Optical Encoder

IP.com Disclosure Number: IPCOM000116315D
Original Publication Date: 1995-Aug-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 58K

Publishing Venue

IBM

Related People

MacGregor, A: AUTHOR

Abstract

Two optical wave guide circuits are depicted that will promote an increase in system reliability while reducing overall product cost and physical size of an optical encoder package in comparison with an equivalent design using multiple fused couplers.

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Optical Wave Guide Circuit for Multi-Axis Optical Encoder

      Two optical wave guide circuits are depicted that will promote
an increase in system reliability while reducing overall product cost
and physical size of an optical encoder package in comparison with an
equivalent design using multiple fused couplers.

      A single axis optical encoder system that is based on a
reflected signal, similar to existing CD ROM technology, may require
multiple data signals to guarantee desired positional accuracy.  A
system is described whereby the input signal is delivered to the
reflective optical encoder over a fiber optic line.  The reflected
return signal travels back through the same fiber optic line, through
a 1X2 fused coupler and to a detector.  The circuit design described
here assumes that 3 data signals are required per axis and that a 4
axis system is being built.  This design criteria implies the
following:  the total system will require twelve sources, twelve
detectors and twelve 1X2 fused couplers.

      The use of wave guides should allow the mass production of
various coupling elements in a repeatable fashion such that a more
reliable system design with fewer components and ultimately a lower
manufacturing cost is possible.  Below are two examples of how
single-mode wave guide circuits could result in a more reliable lower
cost system.  Fig. 1 represents a design that incorporates one 1X4
and four 1X2 wave guide couplers on a single substrate t...