A new type of edge-guided mode (E. G. Mode) isolator is proposed, which has the following desirable characteristics: (a) high isolation (more than 40 dB with 1dB insertion loss), (b) simple structure without additional lossy materials, and (c) considerably broad band (40% relative bandwidth). Moreover, a new type of E. G. mode circulator for which the scattering matrix is of the non-cyclic from is also proposed.