| 摘要 |
PURPOSE:To reduce production cost by providing an optical switch with a magneto-optical element having 90 deg. Faraday rotational angle, the 1st and 2nd polarizers arranged on the front and back positions in the optical path of said element and an impressed magnetic field control means for controlling a magnetic field to be impressed to said element. CONSTITUTION:The optical switch is provided with the magneto-optical element 20 set up to a length so as to have 90 deg. Faraday rotational angle, the 1st and 2nd polarizing prisms 22, 24 arranged in the optical path of the element 20 and the impressed magnetic field control means capable of optionally turning on/off an external magnetic field to be impressed to the element 20. In this case, a straight polarized P component passed through the 1st prism 2 is made incident upon the element 20. Since the external magnetic field generated around a coil by current based upon a power supply 30 and a resistor 34 is applied to the element 20, the incident straight polarized P component is rotated by 90 deg. at its polarizing face and projected to the 2nd optical prism 24 as an S component. However, the S component can not be passed because the polarizing face direction is different by 90 deg.. Thus, the passage and interruption of light can be easily controlled by turning on and off the switch 32.
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