Tapered optical fiber, manufacturing method thereof and manufacturing system thereof

A manufacturing method of a tapered optical fiber, comprising:

• a reciprocating step of reciprocates an optical fiber in the direction of the optical axis of the optical fiber by controlling mounting unit that fixes the optical fiber at mounting positions, the mounting positions be spaced apart from each other in the direction of the optical axis;
• and
• a heating step of heating the reciprocating optical fiber at a fixed position that is located between the mounting positions,
• wherein, in the reciprocating step, at least one of a range of reciprocal movement of the mounting unit, reciprocal movement speed of the mounting unit, and broadening width of the optical fiber is changed, the optical fiber having a tapering profile that has at least one inflection portion, the inflection portion having a rate of change in an outer diameter that substantially decreases relative to the rate of change in the outer diameter of taper portions directly adjacent to the inflection portion.

A tapered optical fiber extended seamlessly in a direction of the optical axis, and manufactured by a manufacturing system of the tapered optical fiber, the manufacturing system comprising

• a mounting unit that fixes an optical fiber at mounting positions that are spaced apart from each other in a direction of the optical axis of the optical fiber;
• a shifter that reciprocates the optical fiber in the direction of the optical axis by controlling the mounting unit;
• and
• a heating device that heats the reciprocating optical fiber at a fixed position that is located between the mounting positions,
• wherein the shifter changes at least one of a range of reciprocal movement of the mounting unit, reciprocal movement speed of the mounting unit, and broadening width of the optical fiber, and
• wherein the resulting optical fiber has a tapering profile that has at least one inflection portion, the inflection portion having a rate of change in an outer diameter that substantially decreases relative to the rate of change in the outer diameter of taper portions directly adjacent to the inflection portion, and
• the tapered optical fiber, comprising:
• an end portion;
• and
• a thin portion that is tapered toward the center of the tapered optical fiber by gradually reducing an outer diameter of the thin portion in size from an side of the end portion toward the center, wherein
• the thin portion has one or more inflection portion that is different in the rate of change in the outer diameter of the thin portion from the other portion of the thin portion or the other inflection portion.