Abstract: An optical isolator is placed in the path of an input optical fiber and an output optical fiber, the optical isolator comprises: a first GRIN lens for receiving rays emitted from the input optical fiber and converging into parallel rays; a first birefringent crystal wedge for splitting the parallel rays into a first ray polarized along the birefringent crystal's optical axis and a second ray polarized perpendicularly to the optical axis; a second birefringent crystal wedge for recombining the first ray and the second ray wherein at least one of the first birefringent crystal wedge and the second birefringent crystal wedge comprises a birefringent crystal of YVO.sub.