US 11,754,465 B2
Optical pulse testing device and optical pulse testing method
Atsushi Nakamura, Musashino (JP); Nazuki Honda, Musashino (JP); Daisuke Iida, Musashino (JP); Hiroyuki Oshida, Musashino (JP); and Keiji Okamoto, Musashino (JP)
Assigned to NIPPON TELEGRAPH AND TELEPHONE CORPORATION, Tokyo (JP)
Appl. No. 17/426,631
Filed by NIPPON TELEGRAPH AND TELEPHONE CORPORATION, Tokyo (JP)
PCT Filed Sep. 4, 2019, PCT No. PCT/JP2019/034867
§ 371(c)(1), (2) Date Jul. 28, 2021,
PCT Pub. No. WO2020/158033, PCT Pub. Date Aug. 6, 2020.
Claims priority of application No. 2019-013566 (JP), filed on Jan. 29, 2019.
Prior Publication US 2022/0120635 A1, Apr. 21, 2022
Int. Cl. G01M 11/00 (2006.01)
CPC G01M 11/3127 (2013.01) [G01M 11/3145 (2013.01); G01M 11/3154 (2013.01)] 6 Claims
OG exemplary drawing
 
1. An optical pulse test apparatus comprising:
a light incident unit configured to input test optical pulses having predetermined spectral widths on one end of an optical fiber under test, the optical fiber under test including a connection portion at which optical fibers are connected to each other;
a light receiving unit configured to receive backscattered light by the test optical pulses from one end of the optical fiber under test and obtain a light intensity distribution with respect to a longitudinal direction of the optical fiber under test; and
a computation unit configured to calculate a reflection peak value caused by Fresnel reflection generated at the connection portion of the optical fiber under test from the light intensity distribution, and determine a type of medium at the connection portion of the optical fiber under test, based on the reflection peak value;
wherein the light incident unit sequentially inputs the test optical pulses having different center wavelengths on one end of the optical fiber under test, and
the computation unit determines a type of medium at the connection portion of the optical fiber under test, based on an average value obtained by averaging the reflection peak values determined for each of the test optical pulses having different center wavelengths.