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 ( 3 c) of 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 ( 6 c) 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 ).
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