IN-LINE OPTICAL ISOLATOR

摘要

In conventional optical isolators, an optical signal is dispersed by polarization or the characteristics are varied by heat generation in a garnet crystal. According to the invention, the crystal optical axis (3c) of a rutile crystal (3) is oriented so that the separation directions of the ordinary ray O and the extraordinary ray E are perpendicular to the plane including the optical axes of optical fibers (10, 11). Furthermore, the focusing central optical axis (6c) of a focusing rod lens (6) is arranged parallel with optical axes of the optical fibers (10, 11) and at a substantially equal distance from the four rays, i.e. the ordinary ray O and the extraordinary ray E propagating along the optical axis of the optical fiber (10) and the ordinary ray O and the extraordinary ray E propagating along the optical axis of the optical fiber (11). An air gap (7) of about 200 [mum] is provided, as a heat insulating means, between the focusing rod lens (6) and a magnetized garnet crystal (8).