JP2853663B

PROBLEM TO BE SOLVED: To provide an integrated optical circuit which is small in size and has low losses and also is enabled to be operated at a low voltage. SOLUTION: This circuit is constituted so that the radius of curvature of an external curved optical waveguide 2 constituting an optical waveguide is made smaller then that of an internal curved optical waveguide 13 constituting an optical control device (optical switching element) 1 by making radiuses of curvature of the external curved waveguide 2 constituting the optical waveguide which guides an optical signal and the internal curved optical waveguide 13 constituting the optical control device 1 to be optically connected to this optical waveguide different. Thus, respective excessive losses in the optical control device and the optical waveguide are reduced, the miniaturizing of an integrated optical circuit is realized because the radiuses of curvature are prevented from becoming larger uselessly and the circuit is made possible to be operated in a low voltage by lengthening effective lengths of electrodes in the optical control device.