INTER-MODE GROUP DELAY DIFFERENCE MEASURING DEVICE AND METHOD

Title:

INTER-MODE GROUP DELAY DIFFERENCE MEASURING DEVICE AND METHOD

Document Type and Number:

WIPO Patent Application WO/2024/024094

Kind Code:

A1

Abstract:

The purpose of the present invention to provide an inter-mode group delay difference measuring device and method that can measure a DMD with a simple configuration even if an FMF to be measured is at a long distance.　An inter-mode group delay difference measurement device 301 according to the present invention comprises: a light source 11 that outputs coherent light for which the optical frequency is changed at a predetermined modulation period; a branching element 12 that branches the light into two; a light input unit 13 that excites one branched light into a plurality of modes, guides the excited light into one end of an optical fiber 51 to be measured, the optical fiber 51 to be measured being a multi-mode optical fiber, and inputs the other branched light into one end of a reference optical fiber 52 in a single mode; an image sensor 15 that observes the interference light between the measurement light emitted from the other end of the optical fiber 51 to be measured and the reference light emitted from the other end of the reference optical fiber 52; and a computing unit 16 that detects the peaks of the interference light that appears when the modulation period is changed and measures the inter-mode group delay difference from the period of the peaks and the electric field distribution of the interference light at the peaks.

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Inventors:

ODA TOMOKAZU (JP)
TAKAHASHI HIROSHI (JP)
NAKAMURA ATSUSHI (JP)
KOSHIKIYA YUSUKE (JP)

Application Number:

PCT/JP2022/029324

Publication Date:

February 01, 2024

Filing Date:

July 29, 2022

Export Citation:

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Assignee:

NIPPON TELEGRAPH & TELEPHONE (JP)

International Classes:

G01M11/02

Foreign References:

JP2006267107A	2006-10-05
KR100725211B1	2007-06-04

Other References:

ABE YUTA; OKAMOTO ATSUSHI; OGAWA KAZUHISA; TOMITA AKIHISA; SOMA DAIKI; WAKAYAMA YUTA; TSURITANI TAKEHIRO: "Collective measurement of DMD in 6-mode 19-core fiber using low-coherence digital holography", SPIE PROCEEDINGS, SPIE, US, vol. 11309, 31 January 2020 (2020-01-31), US , pages 1130904 - 1130904-6, XP060127664, ISBN: 978-1-5106-3673-6, DOI: 10.1117/12.2545360

Attorney, Agent or Firm:

OKADA, Kenji et al. (JP)

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