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Title: Different measures of speckle and coherence at the output of a multimode optical fiber

Abstract

Excitation of a multimode fiber with a focused spatially coherent light of finite bandwidth results in a partially coherent light at the output of the fiber. In this report, we observe the properties of speckle and classical coherence of such light with analytical theory, numerical modeling, and experimentally. Of particular interest is the relationship between measures of coherence and speckle and their dependence on input source bandwidth and fiber length. Speckle contrast is easy to measure experimentally and there exist at least two different methods to generate ensembles of random speckles. We demonstrate that speckle contrast evaluated over the ensemble of external diffusers is related to the number of effective modes—one of the characteristics of beam global coherence. The other speckle contrast measure evaluated over the ensemble of random bends and twists of the fiber is related to residual coherence, which is the pedestal on the average modulus of the complex degree of the coherence function on the output endface of the fiber.

Authors:
ORCiD logo [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1571610
Alternate Identifier(s):
OSTI ID: 1484401
Report Number(s):
LA-UR-18-27749
Journal ID: ISSN 1084-7529; JOAOD6
Grant/Contract Number:  
89233218CNA000001; AC52-06NA25396
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of the Optical Society of America. A, Optics, Image Science, and Vision
Additional Journal Information:
Journal Volume: 36; Journal Issue: 1; Journal ID: ISSN 1084-7529
Publisher:
Optical Society of America (OSA)
Country of Publication:
United States
Language:
English
Subject:
47 OTHER INSTRUMENTATION

Citation Formats

Efimov, Anatoly. Different measures of speckle and coherence at the output of a multimode optical fiber. United States: N. p., 2018. Web. doi:10.1364/JOSAA.36.000001.
Efimov, Anatoly. Different measures of speckle and coherence at the output of a multimode optical fiber. United States. https://doi.org/10.1364/JOSAA.36.000001
Efimov, Anatoly. Thu . "Different measures of speckle and coherence at the output of a multimode optical fiber". United States. https://doi.org/10.1364/JOSAA.36.000001. https://www.osti.gov/servlets/purl/1571610.
@article{osti_1571610,
title = {Different measures of speckle and coherence at the output of a multimode optical fiber},
author = {Efimov, Anatoly},
abstractNote = {Excitation of a multimode fiber with a focused spatially coherent light of finite bandwidth results in a partially coherent light at the output of the fiber. In this report, we observe the properties of speckle and classical coherence of such light with analytical theory, numerical modeling, and experimentally. Of particular interest is the relationship between measures of coherence and speckle and their dependence on input source bandwidth and fiber length. Speckle contrast is easy to measure experimentally and there exist at least two different methods to generate ensembles of random speckles. We demonstrate that speckle contrast evaluated over the ensemble of external diffusers is related to the number of effective modes—one of the characteristics of beam global coherence. The other speckle contrast measure evaluated over the ensemble of random bends and twists of the fiber is related to residual coherence, which is the pedestal on the average modulus of the complex degree of the coherence function on the output endface of the fiber.},
doi = {10.1364/JOSAA.36.000001},
url = {https://www.osti.gov/biblio/1571610}, journal = {Journal of the Optical Society of America. A, Optics, Image Science, and Vision},
issn = {1084-7529},
number = 1,
volume = 36,
place = {United States},
year = {2018},
month = {12}
}

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Cited by: 3 works
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