To provide a method of precisely estimating the angle deviation amount of the plane of polarization of a constant-polarization optical fiber when the optical fiber is connected.
The side face of the constant-polarization optical fiber 1 is irradiated with light, and the distribution of the luminance of transmitted light is found. Positions and heights of two luminance peaks 1e, 1f are changed by the angle deviation amount of a polarization axis 1c connecting two stress giving parts 1a, 1b with reference to the irradiation direction of the light. On the basis of the peak positions and the peak heights, the angle deviation amount is estimated, and the optical fiber 1 is connected with high accuracy without causing the angle deviation of the plane of polarization.
SAITO SHIGERU
KAWANISHI NORIYUKI
