| 摘要 |
A method of measuring the spot size of a single-mode optical fiber (8, 14), comprising the steps of measuring the far field pattern (FFP) of a beam emitted from one end (10) of the single-mode optical fiber (8,14) in a range from the radiation angle, at which the far field pattern (FFP) is maximum, to the radiation angle at which the far field pattern is reduced 25 dB or smaller, calculating the near field pattern (NFP) from the measured far field pattern (FFP) by the use of Hankel transform, and determining the spot size from the calculated near field pattern (NFP) according to a prescribed definition formula. |
