OPTICAL CIRCULATOR AND OPTICAL SWITCH

PROBLEM TO BE SOLVED: To provide an optical circulator of which size can be reduced. SOLUTION: A collimater lens 12, a taper plate 13, a 1st composite polarizing prism 14, a non-reciprocal part 15, a 2nd composite polarizing prism 16, and a collimater lens 17 are successively arranged from the two-core ferrule side between a two-core ferrule 10 including two parallel optical fiber cores 1, 3 and a ferrule including an optical fiber core 2. Exit light from an optical fiber core 3 is passed through a position deviated from the center axis of the collimater lens 12, refracted, corrected so as to be parallel with the optical axis of the port 3 by the taper plate 13 and made incident upon the prism 16. Since the optical fiber cores 1, 3 can be brought extremely close to each other and included in one two-core ferrule 10 and the numbers of ferrules and collimater lenses 12 can be reduced, the whole device can be reduced in size.