| 摘要 |
PURPOSE:To form a coupler which prevents variation in operation characteristics with time and operates stably by coupling a polarization plane maintaining optical fiber with another optical component so that their axes have <=5 deg. angle deviation at a maximum. CONSTITUTION:When the polarization plate maintaining optical fiber 5 with an elliptic core is coupled with a directional coupling type optical switch 4 made of LiNbO3, the coupler with a mark which indicates the axial direction in optical fiber section is used to couple them with each other to <=5 deg. angle deviation at a maximum. When the optical fiber 5 is coupled to, for example, 3 deg. deviation, time variation in the quantity of projection light from the output 6 of the optical fiber 6 which is measured throughout about one year is <=0.1%. Consequently, the coupler which prevents variation in characteristics with time and operates stably is obtained. |
