Title:
OPTICAL LINE TESTING DEVICE AND OPTICAL LINE TESTING METHOD
Document Type and Number:
WIPO Patent Application WO/2024/028939
Kind Code:
A1
Abstract:
Provided are an optical line testing device and an optical line testing method, by which output light from a laser light source is split into a probe light path and a local light path, and modulated light, which is obtained by modulating the light input into the probe light path, is converted into probe light containing pulsed light. Signal light, which is emitted from one end of an optical fiber when the probe light is made to enter one end thereof, and the input light of the local light path are caused to interfere with each other to generate a beat signal; a signal representing backscattered light in the optical fiber is acquired on the basis of the beat signal; and a loss distribution is analyzed. In generating the modulated light, during a period in which the frequency of the light outputted from the laser light source is continuous, a first conversion is performed in which a plurality of modulations are sequentially executed on the basis of at least two or more mutually different first frequencies, and a second conversion is performed on the basis of a second frequency that changes by a predetermined change amount each time, for each cycle of the pulsed light. Backscattered light in each different frequency band contained in the beat signal is averaged across the different frequency bands to generate a signal for analysis, and the strength of the backscattered light contained in the signal for analysis is analyzed to acquire the loss distribution.
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Inventors:
TAKAHASHI HIROSHI (JP)
WAKISAKA YOSHIFUMI (JP)
IIDA DAISUKE (JP)
KOSHIKIYA YUSUKE (JP)
WAKISAKA YOSHIFUMI (JP)
IIDA DAISUKE (JP)
KOSHIKIYA YUSUKE (JP)
Application Number:
PCT/JP2022/029467
Publication Date:
February 08, 2024
Filing Date:
August 01, 2022
Export Citation:
Assignee:
NIPPON TELEGRAPH & TELEPHONE (JP)
International Classes:
G01M11/02
Domestic Patent References:
| WO2022044174A1 | 2022-03-03 |
Foreign References:
| JP2020169904A | 2020-10-15 |
Other References:
SHIMIZU, KAORU.: "Characteristics and reduction of coherent fading noise in Rayleigh backscattering measurement for optical fibers and components", JOURNAL OF LIGHTWAVE TECHNOLOGY, vol. 10, no. 7, 1992, pages 982 - 987, XP000301489, DOI: 10.1109/50.144923
KITO, CHIHIRO.: "Field Measurement of PON Branches With End-Reflection-Assisted Brillouin Analysis", JOURNAL OF LIGHTWAVE TECHNOLOGY, vol. 34, no. 19, 2016, pages 4454 - 4459, XP055813978, DOI: 10.1109/JLT.2016.2531081
WAKISAKA, YOSHIFUMI.: "Fading Suppression of PHI-OTDR With the New Signal Processing Methodology of Complex Vectors Across Time and Frequency Domains", JOURNAL OF LIGHTWAVE TECHNOLOGY, vol. 39, no. 13, 2021, pages 4279 - 4293, XP011862146, DOI: 10.1109/JLT.2021.3071159
KITO, CHIHIRO.: "Field Measurement of PON Branches With End-Reflection-Assisted Brillouin Analysis", JOURNAL OF LIGHTWAVE TECHNOLOGY, vol. 34, no. 19, 2016, pages 4454 - 4459, XP055813978, DOI: 10.1109/JLT.2016.2531081
WAKISAKA, YOSHIFUMI.: "Fading Suppression of PHI-OTDR With the New Signal Processing Methodology of Complex Vectors Across Time and Frequency Domains", JOURNAL OF LIGHTWAVE TECHNOLOGY, vol. 39, no. 13, 2021, pages 4279 - 4293, XP011862146, DOI: 10.1109/JLT.2021.3071159
Attorney, Agent or Firm:
MIYOSHI Hidekazu et al. (JP)
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