Thomas Y. L. Ang, Jun Rong Ong, Ezgi Sahin, Bryan Pawlina, George F. R. Chen, Dawn T. H. Tan, Soon Thor Lim, Ching Eng Png: Broadband and Fabrication Tolerant Silicon Polarization Beam Splitters with Ultra-high Extinction Ratio of 40 dB. OFC 2018: 1-3