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IMPROVED MULTIREFLECTION MULTI/DEMULTIPLEXER FOR OPTICAL FIBER COMMUNICATION

IP.com Disclosure Number: IPCOM000025025D
Original Publication Date: 1983-Apr-30
Included in the Prior Art Database: 2004-Apr-04
Document File: 4 page(s) / 169K

Publishing Venue

Xerox Disclosure Journal

Abstract

Low loss optical multi/demultiplexer devices are a necessary component to optical fiber communication. Various optical wavelengths must be efficiently multiplexed for transmission and demultiplexed at one or more points in an optical fiber communication system for subsequent processing.

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IMPROVED MULTIREFLECTION MULTI/DEMULTIPLEXER FOR OPTICAL FIBER COMMUNICATION
W. Douglas Carothers, Jr.

Proposed Classification
U.S. C1. 370/3 Int. Cl. H04j 1/00

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IMPROVED MULTIREFLECTION MULTI/DEMULTIPLEXER FOR OPTICAL FIBER COMMUNICATION (Cont'd)

  XEROX DISCLOSURE JOURNAL Volume 8 Number 2 March/April 1983

172

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IMPROVED MULTIREFLECTION MULTI/DEMULTIPLEXER FOR OPTICAL FIBER COMMUNICATION (Cont'd)

cemented to the pentagon side faces. The input/output connections comprise an optical fiber 18 coupled to a collimating lens 20. Input/output lens 20 is secured to a glass spacer 22 by means of epoxy.

Each of the other lens 20 and coupled fibers 18 are aligned and cemented to triangular shaped glass spacers 24 after spacers 24 are secured to the surface of a respective filter 14. Spacers 24 are all geometrically identical. Since the pentagon 12 and its faces and spacers 22 and 24 are easily prefabricated on a mass basis to proper angles and size, alignment may be easily achieved in the assembly of all components comprising the device 10.

Low loss optical multi/demultiplexer devices are a necessary component to optical fiber communication. Various optical wavelengths must be efficiently multiplexed for transmission and demultiplexed at one or more points in an optical fiber communication system for subsequent processing.

In US. Patent 4,244,045, a multiplexer structure is fabricated by employing a rectangular glass substrate on the major surfaces of which are deposited dielectric thin film layers forming independent interference filters. Each filter is capable of passing a particular wavelength. A collimating lens, coupled to an optical fiber, is cemented to each of the filters at an angular position to receive an internally reflected light beam coupled out of the glass substrate or coupled from the lens into the glass substrate.

One problem with this structure is the difficulty of fabrication. For example, the interference filters must be properly positioned and aligned or deposited on the surfaces of the substrate. Next, the angular arrangement of the lenses must be determined and positioned properly upon its respective filter. To be noted is the
.difficulty encountered in aligning the filters and lenses to be in accurate axial alignment with the incident light...