In this study, we propose a simple and applicable approach to analyze the large angle (larger than 10 degrees) abrupt bent waveguides, By using the conformal mapping technique, the abrupt bent waveguide is transformed into an equivalent straight one which the conventional (paraxial) beam propagation method (BPM) can be applied to analyze it directly, The field distribution in a 20 degrees microprism type abrupt bent waveguide is also demonstrated by our method.
