| 摘要 |
PURPOSE:To obtain high coupling efficiency by setting the angle of incidence on an optical isolator so that a projection light beam does not become elliptic. CONSTITUTION:In the basic constitution of a laser diode (LD) module constituted by using the optical isolator, a light beam 38 which is emitted by an LD 32 and passed through a lens 34 to have an axially symmetric beam spread 36 is made incident on the 1st polarizing prism 20 of the optical isolator 18 at an angle theta0 of incidence to become a light beam 40 which has an optical axis parallel to the optical axis of the light beam 38 when projected. In this case, the angle of incidence is set to theta0 so that the ellipticity epsilon of the projection beam pattern is 0, so the beam pattern 39 of the light beam 40 projected from the 2nd polarizing prism 22 becomes axially symmetrical and can be guided efficiently to a single-mode optical fiber SMF 44 by a lens 42. |
