DESIGN AND APPLICATION OF VERY LOW-LOSS ABRUPT BENDS IN OPTICAL WAVE-GUIDES

A new low-loss abrupt bend structure of the microprism type is proposed. This new bend uses a microprism to compensate for the phase difference of the phase front before and after the bend corner, so the entire phase front of the eigenmode is tilted properly, resulting in a very low-loss characteristic. Simulated results show that a normalized transmitted power of greater than 95% is achieved for a bend angle of 10 degrees. Moreover, a phase compensation rule and its corrections are presented to determine the optimal prism parameters. Application examples of the microprism to design a very low-loss large-angle Z-bend and two cascaded Z-bends are also shown.