A polarization splitter (PS) based on a directional coupler (DC) composed of vertical multiple-slotted waveguide (MSW) and silicon nanowire is proposed and designed by using a modified three-dimensional full-vectorial beam propagation method (BPM). By utilizing the unique modal properties of the slot waveguide, the coupling of the DC in quasi-TE modes can be almost neglected, and only that in quasi-TM is considered, leading to a compact PS. Moreover, the MSW has the advantages of both strong field confinement and high birefringence, which improves the performance of the present device. The numerical results show that a PS with a length of 20.5μμm in the coupling region is achieved whose bandwidth is up to 22nm (ranged from 1.540 to 1.562μm) with the crosstalk lower than -20dB. In addition, the fabrication tolerances to the structural parameters are investigated in detail. And the evolution of the injected field along the propagation distance through the PS is also demonstrated.

Date Published: 14 March 2013
PDF: 12 pages
Proc. SPIE 8619, Physics and Simulation of Optoelectronic Devices XXI, 86191U (14 March 2013); doi: 10.1117/12.2000625

Published in SPIE Proceedings Vol. 8619:
Physics and Simulation of Optoelectronic Devices XXI
Bernd Witzigmann; Marek Osinski; Fritz Henneberger; Yasuhiko Arakawa, Editor(s)