A novel low-loss wide-angle Y-branch with a diamond-like microprism

A novel structure of low-index diamond-like microprism on a single-mode symmetric Y-junction waveguide is proposed. Not only the phase-front mismatch can be compensated, but also the field mismatch can be ameliorated with the help of power presplitting effect. The optimal prism parameters are determined, and the results simulated by beam propagation method also demonstrate that the transmitted loss is only 0.6 dB even though the branching angle is up to 20/spl deg/. Moreover, this structure takes many advantages of the simple structure, easy design procedure, being fairly insensitive to fabrication errors, and flexible selection of prism-index.