A computer-aided design system for integrated devices is described, combining guided-wave circuit layout design and beam-propagation simulation of waveguide optics. The layout design includes efficient ways of generating various waveguide routing geometries, interfaced with generation of data on the lithographic mask geometry and with a simulator of optical propagation through waveguide devices. The optical simulator includes two alternative algorithms for the beam-propagation method algorithms. Additional modules connected with specific waveguide fabrication technologies are described. Calculation examples are included, applying the system to problems handled in published literature.