Abstract: An optical isolator comprises two polarizers arranged before and after an optical rotator and a magnet surrounds the optical rotator. The magnet may generate a magnet field with a direction in spatial space parallel to the propagation direction of light traveling in the optical rotator and a strength sufficient to rotate the light to a predetermined rotation angle. Preferably, the polarizers are birefringent wedges of identical shape and optical properties. The magnet in accordance with the present invention may have a pair of magnetic adapters to generate the desired direction and strength of magnetic field. The direction of magnetic field varies in three-dimension space as the magnet is adjusted. The present invention provides an optical isolator of high isolation for high-volume mass production at a low cost. In particular, it may be easily operated at different wavelengths to achieve desired isolation without sacrifice of other optical properties of the optical isolator.