| 摘要 |
PURPOSE: To provide an optical isolator with high quenching performance and joining strength by making a thermal expansion coefficient of a holder smaller than a polarizing plate and making the thermal expansion coefficient of a spacer larger than the polarizing plate. CONSTITUTION: Joining material of a thermo-melting property is filled up between the holders 2, 3 and the polarizing plates 4, 5 and between the polarizing plates 4, 5 and the spacers 11, 12, and the thermal expansion coefficient of the holders 2, 3 is made smaller than the same of the polarizing plates 4, 5, and the same of the spacers 11, 12 is made larger than the same of the polarizing plates 4, 5. Thus, no distortion caused by contraction is concentrated to the polarizing plates 4, 5. Further, when a Faraday rotator 8 is joint fixed to one side spacer 11, since the thermal expansion coefficient of the Faraday rotator 8 is nearly equal to the same of the spacer 11, the joint distortion of the Faraday rotator 8 is reduced. Further, the thermal expansion coefficient of the holders 2, 3 is 6.5×10<-6> / deg.C or below, and the same of the spacers 11, 12 is larger than 6.5×10<-6> / deg.C and smaller than 12×10<-6> / deg.C.
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