Optical passive components

摘要

An object of the present invention is to provide an optical passive component having a polarization-independent optical isolator for constituting an optical fiber amplifier and exhibiting an optical isolator function. At least first and second optical fibers for input and output of light rays, a birefringent crystal, a lens for converting the input light rays into nearly collimated rays, a magnetooptical crystal for receiving a magnetic field so as to rotate by pi /8+N pi /4(n=0, 1, . . . ) the polarization direction of the input light rays, and a reflector are disposed in order. A half wave plate is provided to cover one portion of the ray path between the above described birefringent crystal and the above described lens.