Method for measuring crosstalk between spatial channels, and device for measuring crosstalk between spatial channels

An inter-spatial-channel crosstalk measurement apparatus for measuring crosstalk between spatial channels of a space division multiplexing optical fiber having a first entrance/exit surface and a second entrance/exit surface and having N spatial channels (with N being an integer of 2 or more), the inter-spatial-channel crosstalk measurement apparatus comprising:

• a light source configured to cause test light to enter the N spatial channels on the first entrance/exit surface;
• a light reflection suppressor formed or provided on the second entrance/exit surface and configured to suppress reflection of the test light;
• an optical detector configured to detect a first optical power and a second optical power, the first optical power being a power of light of at least part of the test light and being a power of light emitted from a first spatial channel that the test light enters, the second optical power being a power of light of the at least part of the test light and being a power of light emitted from a second spatial channel different from the first spatial channel, the at least part of the test light having undergone Rayleigh backscattering in the space division multiplexing optical fiber;
• and
• a calculator configured to calculate a magnitude of crosstalk between the first spatial channel and the second spatial channel, based on the first optical power and the second optical power.