| 摘要 |
PURPOSE:To reduce elements which constitute an optical isolator in size and cost by arranging the optical isolator which consists of a Faraday rotator and an analyzer between a non-confocal photocoupler and an optical fiber where a light beam is reduced in diameter most. CONSTITUTION:The non-confocal photocoupler which consists of the 1st converging rod lens 13a have a convex surface as its end surface on the side of a semiconductor laser 11 and the 2nd converging rod lens 13b whose end surfaces are both plane is used as a photocoupler which couples the semiconductor laser 11 with the optical fiber 12 optically. The optical isolator 14 consists of the Faraday rotator 14a and analyzer 14b, which are united together on the flank of the 2nd converging rod lens 13b on the side of the optical fiber. The Faraday rotator 14a consists of a thin magnetic material film 15 and a magnet 16 and is sufficiently thin and its necessary saturated magnetic field is small, so the magnet 16 may be small in size; and the analyzer 14b is close to the fiber end surface, so its thickness is irreducible. Thus, the optical isolator is economized while reduced in size. |
