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Title: Lensless Magneto-optic speed sensor

Abstract

Lensless magneto-optic speed sensor. The construction of a viable Faraday sensor has been achieved. Multimode fiber bundles are used to collect the light. If coupled directly into a 100 or 200 .mu.m core fiber, light from a light emitting diode (LED) is sufficient to operate the sensor. In addition, LEDs ensure that no birefringence effects in the input fiber are possible, as the output from such light sources have random polarization. No lens is required since the large diameter optical fibers and thin crystals of materials having high Verdet constants (such as iron garnets) employed permit the collection of a substantial quantity of light. No coupler is required. The maximum amount of light which could reach a detector using a coupler is 25%, while the measured throughput of the fiber-optic bundle without a coupler is about 42%. All of the elements employed in the present sensor are planar, and no particular orientation of these elements is required. The present sensor operates over a wide range of distances from magnetic field sources, and observed signals are large. When a tone wheel is utilized, the signals are independent of wheel speed, and the modulation is observed to be about 75%. No sensitivitymore » to bends in the input or output optical fiber leads was observed. Reliable operation was achieved down to zero frequency, or no wheel rotation.« less

Inventors:
 [1];  [1];  [2]
  1. Los Alamos, NM
  2. Santa Fe, NM
Issue Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
OSTI Identifier:
871377
Patent Number(s):
5719497
Assignee:
Regents of University of California (Los Alamos, NM)
Patent Classifications (CPCs):
G - PHYSICS G01 - MEASURING G01P - MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK
G - PHYSICS G01 - MEASURING G01R - MEASURING ELECTRIC VARIABLES
DOE Contract Number:  
W-7405-ENG-36
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
lensless; magneto-optic; speed; sensor; construction; viable; faraday; achieved; multimode; fiber; bundles; collect; light; coupled; directly; 100; 200; core; emitting; diode; led; sufficient; operate; addition; leds; ensure; birefringence; effects; input; output; sources; random; polarization; lens; required; diameter; optical; fibers; crystals; materials; verdet; constants; iron; garnets; employed; permit; collection; substantial; quantity; coupler; maximum; amount; reach; detector; 25; measured; throughput; fiber-optic; bundle; 42; elements; planar; particular; orientation; operates; wide; range; distances; magnetic; field; observed; signals; tone; wheel; utilized; independent; modulation; 75; sensitivity; bends; leads; reliable; operation; zero; frequency; rotation; emitting diode; optic bundle; mode fiber; speed sensor; optical fibers; light source; magnetic field; optical fiber; wide range; light sources; light emitting; sensor operates; zero frequency; output optical; coupled directly; fiber bundle; core fiber; diameter optical; multimode fiber; fiber bundles; fiber-optic bundle; maximum amount; field sources; lensless magneto-optic; magneto-optic speed; /324/250/385/

Citation Formats

Veeser, Lynn R, Forman, Peter R, and Rodriguez, Patrick J. Lensless Magneto-optic speed sensor. United States: N. p., 1998. Web.
Veeser, Lynn R, Forman, Peter R, & Rodriguez, Patrick J. Lensless Magneto-optic speed sensor. United States.
Veeser, Lynn R, Forman, Peter R, and Rodriguez, Patrick J. Thu . "Lensless Magneto-optic speed sensor". United States. https://www.osti.gov/servlets/purl/871377.
@article{osti_871377,
title = {Lensless Magneto-optic speed sensor},
author = {Veeser, Lynn R and Forman, Peter R and Rodriguez, Patrick J},
abstractNote = {Lensless magneto-optic speed sensor. The construction of a viable Faraday sensor has been achieved. Multimode fiber bundles are used to collect the light. If coupled directly into a 100 or 200 .mu.m core fiber, light from a light emitting diode (LED) is sufficient to operate the sensor. In addition, LEDs ensure that no birefringence effects in the input fiber are possible, as the output from such light sources have random polarization. No lens is required since the large diameter optical fibers and thin crystals of materials having high Verdet constants (such as iron garnets) employed permit the collection of a substantial quantity of light. No coupler is required. The maximum amount of light which could reach a detector using a coupler is 25%, while the measured throughput of the fiber-optic bundle without a coupler is about 42%. All of the elements employed in the present sensor are planar, and no particular orientation of these elements is required. The present sensor operates over a wide range of distances from magnetic field sources, and observed signals are large. When a tone wheel is utilized, the signals are independent of wheel speed, and the modulation is observed to be about 75%. No sensitivity to bends in the input or output optical fiber leads was observed. Reliable operation was achieved down to zero frequency, or no wheel rotation.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1998},
month = {1}
}

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Works referenced in this record:

Fiber optic tachometer based on the Faraday effect
journal, January 1989


Improved sensitivity in novel scheme of magneto-optical field sensor
journal, November 1991


Bismuth rare‐earth iron garnet composition for a magneto‐optical wheel rotation rate sensor
journal, April 1991