Fourier-Domain Modal Delay Measurements for Multimode Fibers Optimized for the 850-nm Band in a Local Area Network

Chan-Young KIM  Tae-Jung AHN  

IEICE TRANSACTIONS on Communications   Vol.E96-B   No.11   pp.2840-2844
Publication Date: 2013/11/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E96.B.2840
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Optical Fiber for Communications
modal dispersion,  differential mode delay,  multimode fiber,  local area network,  

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We present transmission- and reflection-type measurement methods for the differential mode delay (DMD) of a multimode optical fiber (MMF) optimized for high-speed local area networks (LANs) for the 850-nm band. Compared with a previously reported transmission-type measurement method for the 1550-nm wavelength band, we demonstrate here high-resolution DMD measurement methods for MMFs in the 850-nm band. As the method is based on a Fourier-domain intermodal interference technique, the measurement sensitivity is ∼60-dB, and it requires a fiber only a few meters in length. The shorter wavelength also allows a threefold improvement in the measurement resolution. The reflection-type measurement technique is a more practical than the transmission-type measurement technique for the field testing of short MMFs already installed in networks. We believe that this method will be a practical tool not only for field testing of short-length MMFs already installed in networks but also for the development of new plastic optical fibers (POFs).