A NEW ITERATIVE METHOD FOR THE ANALYSIS OF LONGITUDINALLY INVARIANT WAVE-GUIDE COUPLERS

In this paper, a new iterative method to solve for the modal indices a nd field profiles of the supermodes of multichannel waveguide structur es is proposed. This method combines the shift inverse power method wi th the simultaneous iteration method, and can be applied to any longit udinally invariant waveguide couplers problem very efficiently. Using this method, the characteristics of the leading supermodes can be obta ined simultaneously. The validity and accuracy of this method are asse ssed by comparing to other existing methods for symmetric to-channel w aveguide couplers. Results are in good agreement. Asymmetric two-chann el and symmetric three-channel waveguide couplers are then considered to show the usefulness and versatility of the proposed method.