OPTICAL CIRCULATOR

PROBLEM TO BE SOLVED: To provide an inexpensive optical circulator whose total size can be reduced and which makes processing and setting of optical elements easier with high accuracy. SOLUTION: The optical circulator has an optical element part produced by disposing birefringent crystals 1 to 4 and birefringent crystals 7 to 10 coupled and arranged as divided into two parts along the propagation direction of light, and disposing a faraday rotator 5 which does not depend on the propagation direction of light, and a 1/2 wavelength plate 6 which depends on the propagation direction of light, both between the crystals 1 to 4 and crystals 7 to 10. The polarization separation directions in each pair of the birefringent crystals 1, 2, birefringent crystals 3, 4, birefringent crystals 7, 8 and birefringent crystals 9, 10 are opposite to each other. The optical axis directions of the birefringent crystals 1, 2 and those of the birefringent crystals 3, 4 are perpendicular to each other, and the optical axis directions of the birefringent crystals 7, 8 and those of the birefringent crystals 9, 10 are also perpendicular to each other. The polarization separation directions of the birefringent crystals 1, 10 and those of the birefringent crystals 2, 9 are identical while the polarization separation direction of the birefringent crystals 3, 8 and that of the birefringent crystals 4, 7 are also identical.