recent development of waveguide nonreciprocal devices, i.e., isolator and circulator, is reviewed. two major difficulties exist for their fabrication. first, form birefringence must be overcome to obtain high te-tm mode conversion efficiency. secondly, both of input and output light must be either te or tm mode. a variety of methods and device structures have been proposed to solve these difficulties. after a brief discussion on advantages and drawbacks of proposed methods and device structures, a new fabrication process of waveguide isolator is described. a device structure which ensures te mode operation was achieved by making adjoining nonreciprocal and reciprocal mode converters by using laser annealing technique faraday and cotton-mouton effects of bi-substituted iron garnet film were used for nonreciprocal and reciprocal mode converters, respectively. growth-induced and stress-induced birefringences of the film were used to cancel the form birefringence. an isolation ratio of 12.5 db was achieved at wavelength of 1.15 mu m with external magnetic field of 100 gauss