US 11,940,321 B2
Photodetection device and laser device
Shinichi Sakamoto, Chiba (JP); and Wataru Kiyoyama, Chiba (JP)
Assigned to Fujikura Ltd., Tokyo (JP)
Appl. No. 17/254,485
Filed by Fujikura Ltd., Tokyo (JP)
PCT Filed Jun. 21, 2019, PCT No. PCT/JP2019/024740
§ 371(c)(1), (2) Date Dec. 21, 2020,
PCT Pub. No. WO2019/245032, PCT Pub. Date Dec. 26, 2019.
Claims priority of application No. 2018-118956 (JP), filed on Jun. 22, 2018.
Prior Publication US 2021/0181015 A1, Jun. 17, 2021
Int. Cl. G01J 1/42 (2006.01); G01J 1/04 (2006.01); G02B 6/42 (2006.01); H01S 3/13 (2006.01); H01S 3/23 (2006.01); G02B 6/28 (2006.01); H01S 3/00 (2006.01)
CPC G01J 1/4228 (2013.01) [G01J 1/0425 (2013.01); G02B 6/4286 (2013.01); H01S 3/1306 (2013.01); H01S 3/2383 (2013.01); G02B 6/2808 (2013.01); G02B 6/429 (2013.01); H01S 3/0014 (2013.01); H01S 3/1305 (2013.01)] 5 Claims
OG exemplary drawing
 
1. A photodetection device comprising:
first optical fibers;
a second optical fiber;
an optical combiner having:
an end face connected to an end face of each of the first optical fibers; and
another end face connected to an end face of the second optical fiber;
a first photodetector that detects an intensity of light propagating through at least one of the first optical fibers;
a second photodetector that detects Rayleigh scattering of light propagating through the second optical fiber; and
a calculator that calculates the intensity of light propagating in a predetermined direction through the first optical fibers or the second optical fiber, from a result of detection by the first photodetector and a result of detection by the second photodetector,
wherein
some, but not all, of the first optical fibers each have another end face that is optically coupled to a light source, and
the first photodetector detects the intensity of the light propagating through the first optical fibers that are not optically coupled to the light source.