A UNIFIED APPROACH FOR THE COUPLED-MODE ANALYSIS OF NONLINEAR-OPTICALCOUPLERS

A unified approach for the coupled-mode analysis of nonlinear optical couplers is proposed. This approach is basically an extension of the w ork of [17] to include optical nonlinearity. After the nonlinear coupl ed-mode theory is established, various basis functions are used as tri al fields to derive coupled-mode equations. It is found that two publi shed coupled-mode theories can in fact be deduced from the proposed on e with individual linear or nonlinear waveguide modes serving as trial fields, thus making the coupled-mode equations from variational princ iple and reciprocity theorem equivalent. Coupled-mode equations based on system modes are also presented. Furthermore, analytical and/or num erical methods for solving coupled-mode equations are included. More r esearch and discussion can be conducted based on the knowledge address ed in this paper.