US 11,754,466 B2
Mode-dependent loss measurement device and mode-dependent loss measuring method
Takemi Hasegawa, Osaka (JP); Tetsuya Hayashi, Osaka (JP); and Yuki Kawaguchi, Osaka (JP)
Assigned to SUMITOMO ELECTRIC INDUSTRIES, LTD., Osaka (JP)
Filed by SUMITOMO ELECTRIC INDUSTRIES, LTD., Osaka (JP)
Filed on Aug. 17, 2021, as Appl. No. 17/445,241.
Application 17/445,241 is a continuation of application No. PCT/JP2020/006927, filed on Feb. 20, 2020.
Claims priority of application No. 2019-030210 (JP), filed on Feb. 22, 2019.
Prior Publication US 2021/0372882 A1, Dec. 2, 2021
Int. Cl. G01M 11/00 (2006.01); G02B 6/02 (2006.01)
CPC G01M 11/333 (2013.01) [G01M 11/335 (2013.01); G02B 6/02042 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A mode-dependent loss measurement device configured to measure a mode-dependent loss of a measurement target optical fiber including a coupled multi-core optical fiber having a plurality of cores extending along a fiber axis and a common cladding surrounding the plurality of cores, the device comprising:
a light source configured to be optically coupled with an input end of an excitation optical fiber including a coupled multi-core optical fiber having a plurality of cores extending along a fiber axis and a cladding surrounding the plurality of cores, the light source configured to input light to the input end of the excitation optical fiber;
a light receiver optically coupled with an output end of the measurement target optical fiber, the light receiver detecting a sum of powers of outputted light beams from a plurality of core end faces positioned on the output end of the measurement target optical fiber during a period in which the light from the light source is inputted to the input end of the excitation optical fiber in a state in which an output end of the excitation optical fiber and an input end of the measurement target optical fiber are optically coupled with each other;
a mode coupled state change means for changing a mode coupled state of the excitation optical fiber; and
an analysis unit comprising a CPU and a memory configured to analyze variations in optical powers detected by the light receiver during a period in which the mode coupled state of the excitation optical fiber is changing, and obtain the mode-dependent loss of the measurement target optical fiber from the variations in the detected optical powers.