Technique for analyzing a spectrum of backscattered light in an optical fiber

Patent metadata

Field	Value
Publication number	US-12298159-B2
Application number	US-202118283498-A
Country	US
Kind code	B2
Filing date	Mar 25, 2021
Priority date	Mar 25, 2021
Publication date	May 13, 2025
Grant date	May 13, 2025

Abstract

The present disclosure generates an optical spectrogram, representing a temporal change in frequency characteristics, using a plurality of spectral data measured by an OFDR measurement instrument at different times, and filters the optical spectrogram in both a time direction and a frequency direction.

First claim

The invention claimed is:

1. An analysis device that generates an optical spectrogram, representing a temporal change in frequency characteristics, using a plurality of spectral data measured by an OFDR measurement instrument at different times, and filters the optical spectrogram in both a time direction and a frequency direction, wherein a width Δv of filtering in the frequency direction is smaller than a frequency resolution of the OFDR measurement instrument.

2. The analysis device according to claim 1 that calculates a spectral shift using the optical spectrogram after filtering.

3. The analysis device according to claim 1 , wherein a width Δt of filtering in the time direction is defined by a cutoff frequency with respect to a spectral shift.

4. The analysis device according to claim 1 , wherein the filtering is a Gaussian filter.

5. A measurement system comprising:
the OFDR measurement instrument; and
the analysis device according to claim 1 that acquires the plurality of spectral data measured by the OFDR measurement instrument at different times.

6. A computer-readable storage medium storing a program for causing a computer to execute as each functional unit included in the analysis device according to claim 1 .

7. A measurement method comprising:
acquiring a plurality of spectral data by measuring backscattered light with an OFDR measurement instrument at different times;
generating an optical spectrogram, representing a temporal change in frequency characteristics, using the plurality of spectral data; and
filtering the optical spectrogram in both a time direction and a frequency direction, wherein a width Δv of filtering in the frequency direction is smaller than a frequency resolution of the OFDR measurement instrument.

Assignees

• Nippon Telegraph & Telephone

Inventors

• Okamoto Tatsuya
• Iida Daisuke
• Koshikiya Yusuke
• Honda Nazuki

Classifications

• G01D5/35361 Primary

  using elastic backscattering to detect the measured quantity, e.g. using Rayleigh backscattering · CPC title

• G01M11/3172

  Reflectometers detecting the back-scattered light in the frequency-domain, e.g. OFDR, FMCW, heterodyne detection · CPC title

• G01L1/242

  the material being an optical fibre · CPC title

• G01K11/32

  using changes in transmittance, scattering or luminescence in optical fibres · CPC title

• G01D5/35358 Primary

  using backscattering to detect the measured quantity · CPC title