Patent ID: 8531656

Claim:
A method for measuring an exit angle of an optical fiber, the method comprising: passing a measurement end of the optical fiber through a through hole of a holder; receiving output light from the measurement end at a light receiving member while rotating the optical fiber using the through hole as a guide; measuring coordinates of at least three points on a locus circle of the output light to calculate a size of the locus circle; and measuring the exit angle of light from the measurement end of the optical fiber on the basis of the size of the locus circle, wherein the through hole of the holder has a small-diameter portion on a front side and a large-diameter portion on a rear side, an inside diameter of the small-diameter portion is 0.1μm to 1.0 μm larger than a diameter of a bare fiber, an inside diameter of the large-diameter portion is larger than a diameter of a sheathed fiber, and a portion between the small-diameter portion and the large-diameter portion is tapered; and the sheathed fiber with a sheath at a leading end thereof removed is inserted from a rear end of the large-diameter portion, and a bare portion obtained by removing the sheath at the leading end of the sheathed fiber is passed into the small-diameter portion to perform measurement.