A numerical method is proposed and implemented for the analysis of propagation characteristics of nonlinear optical couplers. This technique is based on the shooting method. A fourth-order Runge-Kutta method is adopted to solve wave equations in the coupler. An error function is defined to estimate the discrepency between the computed and predicted boundary values. A secant method is then used to evaluate the correction term of the initial guesses. This procedure is performed iterationally for realization of nonlinear couplers with an arbitrary number of branches and varying parameters. (C) 1993 John Wiley & Sons, Inc.