LIGHT CIRCULATOR

PROBLEM TO BE SOLVED: To easily execute positioning work for a port by arranging a reflection board so that a forward light beam from a 1st port is reflected to an optical non-reciprocal part and a light beam reflected from a 2nd part in a reversed direction is not interrupted. SOLUTION: A transparent body 13 provided with a reflection board 15 is obliquely arranged between the optical non-reciprocal part 5 and an optical multiplexing part 10. The board 15 can reflect a forward beam A20 from the 1st port 20 to the non-reciprocal part 5 and is arranged on a position where the progress of a reverse light beam A2 generated from the 2nd port 2 is not interrupted. The beam A20 made incident upon the 1st port 20 collides with the board 15 to change its track to a horizontal direction and is made incident upon a double refraction plate crystal 7A. The beam A20 made incident upon the crystal 7A is separated into ordinary light y1 and extraordinary light x1 by double refraction. Crystal 7B multiplexes these separated light components to one light beam A2.