| 摘要 |
PURPOSE:To obtain an optical isolator which has small insertion loss even when it is used for a light source emitting a nearly circular light beam with an angle of opening that is not reduced enought, by using two convergent rod lenses. CONSTITUTION:On both sides of a Faraday rotator 1 which provides 45 deg. optical rotation, a curved-surface rod lens 2 which has a convex surface 12 and a plane rod lens 3 are adhered and fixed. On both external asides of both the rod lens, the 1st and 2nd birefringent crystal plates 4 and 5 are arranged, and the 2nd birefringent crystal plate 5 is fixed by being bonded to the plane rod lens 3. The 1st and 2nd birefringent crystal plates 4 and 5 are fixed in such a way that planes containing normal lines of their surfaces and an optical axis are at 45 deg., and on surfaces 41, 42, and 51 and the convex surface 21 of the curved- surface rod lens 2, reflection-preventive films are formed. |
