Patent ID: 7050232
Filing Date: 2006-05-23
Classification: G02B,G02F,Y10S

Abstract:
1. An optical circulator comprising: a first separating/combining birefringent element for separating light on the same optical path into shafts of light having an orthogonal relationship with respect to a polarization direction, and for combining shafts of light on different optical paths; a first optical-path controlling birefringent element for controlling a direction of an optical path depending on the polarization direction; a second optical-path controlling birefringent element for controlling a direction of an optical path depending on the polarization direction; a second separating/combining birefringent element for separating light on the same optical path into shafts of light, and for combining shafts of light on different optical paths having an orthogonal relationship with respect to the polarization direction, wherein said first separating/combining birefringent element, said first optical-path controlling birefringent element, said second optical-path controlling birefringent element, and said second separating/combining birefringent element are spaced apart along an optical path in the recited order, and wherein said first optical-path controlling birefringent element and said second optical-path controlling birefringent element are oppositely arranged such that optical axes thereof are symmetrical with respect to an arrangement center thereof; a first polarization rotating member for changing a relationship of the polarization direction of shafts of light passing therethrough from an orthogonal relationship to a parallel relationship, or from a parallel relationship to an orthogonal relationship, said first polarization rotating member being arranged between said first separating/combining birefringent element and said first optical-path controlling birefringent element; a second polarization rotating member for changing a relationship of the polarization direction of shafts of light passing therethrough from an orthogonal relationship to a parallel relationship, or from a parallel relationship to an orthogonal relationship, said second polarization rotating member being arranged between said second optical-path controlling birefringent element and said second separating/combining birefringent element; a ½-wavelength plate for rotating the polarization direction of light on a central optical path 90 degrees, said ½-wavelength plate being arranged between said first optical-path controlling birefringent element and said second optical-path controlling birefringent element; and ports arranged on a side of said first separating/combining birefringent element and on a side of said second separating/combining birefringent element.