Test method and test system

A test method comprising:

• a post-fusion-splicing measurement step comprising:
• identifying a position of a marker of a first multi-core fiber of two multi-core fibers based on a direction in which a predetermined first shape appears in a graph indicative of a direction dependency of a transmitted light intensity of the first multi-core fiber;
• and
• identifying a position of a marker of a second multi-core fiber of the two multi-core fibers based on a direction in which a predetermined second shape appears in a graph indicative of a direction dependency of a transmitted light intensity of the second multi-core fiber, wherein
• each of the two multi-core fibers comprises:
• cores;
• a cladding;
• and
• the marker inside the cladding, and
• the two multi-core fibers are fusion-spliced to each other via respective end surfaces of the two multi-core fibers.

A test method comprising:

• a post-fusion-splicing measurement step comprising:
• identifying a position of a core or a marker of a first multi-core fiber of two multi-core fibers based on a spatial distribution or a direction dependency of a transmitted light intensity of the first multi-core fiber;
• and
• identifying a position of a core or a marker of a second multi-core fiber of the two multi-core fibers based on a spatial distribution or a direction dependency of a transmitted light intensity of the second multi-core fiber, wherein
• each of the two multi-core fibers comprises:
• cores;
• a cladding;
• and
• the marker formed inside the cladding, and
• the two multi-core fibers are fusion-spliced to each other via respective end surfaces of the two multi-core fibers;
• and
• an estimation step of estimating at least one selected from the group consisting of:
• a coupling efficiency or a connection loss of the two multi-core fibers;
• a correspondence relation between core indexes of the cores of the first multi-core fiber and core indexes of the cores of the second multi-core fiber that are optically coupled to the cores of the first multi-core fiber;
• a region including the marker of the first multi-core fiber among regions obtained by dividing the cladding of the first multi-core fiber and a region including the marker of the second multi-core fiber among regions obtained by dividing the cladding of the second multi-core fiber;
• either or both of:
• an amount of overlap between the marker of the first multi-core fiber and the marker of the second multi-core fiber, and an amount of deviation between the marker of the first multi-core fiber and the marker of the second multi-core fiber;
• either or both of:
• an amount of overlap between the cores of the first multi-core fiber and the cores of the second multi-core fiber that are optically coupled to the cores of the first multi-core fiber, and an amount of deviation between the cores of the first multi-core fiber and the cores of the second multi-core fiber that are optically coupled to the cores of the first multi-core fiber;
• and
• polarities of the two multi-core fibers, wherein
• the estimation step is based on either or both of:
• positions of the cores of the first multi-core fiber and positions of the cores of the second multi-core fiber, and
• the position of the marker of the first multi-core fiber and the position of the marker of the second multi-core fiber having been identified in the post-fusion-splicing measurement step.

A test system comprising:

• one or more light sources;
• one or more light detectors;
• and
• one or more control sections, wherein
• at least one of the one or more control sections carries out a post-fusion-splicing measurement step by using the one or more light sources and the one or more light detectors,
• the post-fusion-splicing measurement step comprises:
• identifying a position of a marker of a first multi-core fiber of two multi-core fibers based on a direction in which a predetermined first shape appears in a graph indicative of a direction dependency of a transmitted light intensity of the first multi-core fiber;
• and
• identifying a position of a marker of a second multi-core fiber of the two multi-core fibers based on a direction in which a predetermined second shape appears in a graph indicative of a direction dependency of a transmitted light intensity of the second multi-core fiber,
• each of the two multi-core fibers comprises:
• a cladding;
• and
• the marker inside the cladding, and
• the two multi-core fibers are fusion-spliced to each other via respective end surfaces of the two multi-core fibers.