Browse Prior Art Database

Method for Fabrication of High Bandwidth Fiber Optic Cable

IP.com Disclosure Number: IPCOM000115278D
Original Publication Date: 1995-Apr-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 47K

Publishing Venue

IBM

Related People

Benedict, M: AUTHOR [+2]

Abstract

Disclosed is a method for the fabrication of multimode fiber optic cable with significantly higher bandwidth and distance capabilities than conventional fiber.

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This is the abbreviated version, containing approximately 77% of the total text.

Method for Fabrication of High Bandwidth Fiber Optic Cable

      Disclosed is a method for the fabrication of multimode fiber
optic cable with significantly higher bandwidth and distance
capabilities than conventional fiber.

      It has been shown (1)  that in order to achieve the maximum
bandwidth-distance product, complete mode mixing is required; the
optical power must be uniformly distributed among guided modes
without coupling power into leaky or unguided modes.  It is possible
to introduce periodic perturbations in the fiber which promote mode
mixing without coupling any power into those modes closest to the
cutoff wavelength.  Perturbations in the fiber diameter or refractive
index act like a diffraction grating to couple power between guided
modes if the periodic variation is equal to the beat wavelength
between fiber modes.  For commercial 50 micron core fiber, the
required perturbation in fiber diameter is about 1 millimeter (2) to
achieve mode mixing regardless of input coupling conditions.

      The apparatus required to fabricate optical fiber with a
periodic perturbation in the diameter is shown in the figure.  The
diameter control step of conventional fiber fabrication is modified;
fiber freshly drawn from the furnace is heated by a pulsed laser
source.  The pulse frequency and drawing speed are controlled to
produce variations in the fiber diameter of 1 to 2 microns with a
periodicity of 1 mm.  The fiber cross-section area is proportion...