Systematic design of novel wide-angle low-loss symmetric y-junction waveguides

To construct a low-loss and wide-branching-angle symmetric Y-junction waveguide, a novel structure is proposed. The structure consists of a pair of microprisms for precompensation and a microprism for phase-front acceleration. The structure of the Y-junction and the associated refractive indexes of microprisms are systematically derived. The simulated results using the fast Fourier transformation beam propagation method (FFT-BPM) demonstrate the performances of the proposed structure. The normalized transmitted power is more than 95% even though the branching angle is up to 20°.