SEMIEMPIRICAL RELATION FOR CURVED OPTICAL WAVE-GUIDE DESIGN IN THE EDGE-GUIDED MODE REGIME

A semiempirical relation has been developed for determining the minimu m allowable radius of curvature of a circular waveguide with an edge-g uided fundamental mode. The specified parameters are the wavelength, t he effective refractive index of the waveguide, the lateral index step , and the allowable radiation loss coefficient. This relation was fitt ed and verified against numerically evaluated solutions of Maxwell's e quations in two dimensions for lateral index steps 0.01 < Delta N < 0. 1, for effective indices of refraction 3 < N < 4 (appropriate for the GaAs / AlxGa1-x As system), and for radiation losses of 10(-4) cm(-1) < alpha(r) < 100 cm(-1). The difference between the results of solving Maxwell's equations and the semiempirical relation over these paramet er ranges was determined to be less than 2%.