High precision Cross-correlated imaging in Few-mode fibers

Olena Muliar, Mario A. Usuga Castaneda, Torben Kristensen, Thomas Tanggaard Alkeskjold, Karsten Rottwitt, Jesper Lægsgaard

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The trend of increasing data traffic in conventional communication systems demands utilizing new methods for data transmission, which in combination with traditional techniques, enable overcoming the predicted capacity limit. Mode division multiplexing (MDM), where higher-order modes (HOMs) in a few-mode fiber (FMF) are used as multiple spatial communication channels, comes in this context as a viable approach to enable the optimization of high-capacity links. From this perspective, it becomes highly necessary to possess a diagnostic tool for the precise modal characterization of FMFs. Among existing approaches for modal content analysis, several methods as S2, C2 in time and frequency domain are available. In this contribution we will present an improved time-domain cross-correlated (C2) imaging technique for the experimental evaluation of modal properties in HOM fibers over a broad range of wavelengths. Our modified setup makes it possible to adjust the time resolution of the system according to the needs of the required fiber measurement. We show that by tuning the spectral shape of the source (SuperK EXTREME filtered by SuperK Select), we enhance the time resolution of the system, which allows us to distinguishing differential time delays between HOMs in the picosecond timescale. Broad wavelength scanning in combination with spectral shaping, allows us to estimate the modal behavior of FMF without prior knowledge of the fiber parameters. We performed our demonstration at wavelengths from 850nm to 1100nm which can be easily extended to other wavelengths of interest just by replacing components with the appropriate coating. The method presented here aims to serve as flexible diagnostic tool that can be implemented in MDM systems for judicious evaluation of modal dispersion in FMFs
Original languageEnglish
Title of host publicationProceedings of SPIE
Number of pages7
PublisherSPIE - International Society for Optical Engineering
Publication date2017
Article number101300T
ISBN (Print)9781510607019
Publication statusPublished - 2017
EventNext-Generation Optical Communication: Components, Sub-Systems, and Systems V - San Francisco, CA, United States
Duration: 16 Feb 201618 Feb 2016


ConferenceNext-Generation Optical Communication: Components, Sub-Systems, and Systems V
Country/TerritoryUnited States
CitySan Francisco, CA
SeriesProceedings of SPIE, the International Society for Optical Engineering

Bibliographical note

Copyright 2017 Society of Photo Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic electronic or print reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.


  • Mode division multiplexing
  • Few mode fiber
  • Cross-correlated imaging
  • Mode characterization
  • Higherorder mode


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