Abstract
An ultracompact and broadband polarization beam splitter (PBS) based on the polarization-dependent critical guiding condition of an asymmetrical directional coupler is proposed. The device consists of a pair of silicon waveguides with different height and width. Due to the different cutoff conditions for the TE and TM polarization modes, it is possible to have the TM mode guided in one waveguide while the TE mode is supported in both. Therefore, only the phase-matching condition for the cross-coupling of the TE mode needs to be considered. This approach not only simplifies the design procedures but also significantly improves device performance with smaller total length and larger bandwidth. Finally, regardless of the contribution of S-bend waveguides, our proposed PBS has a coupling region as short as 0.2 μm, which is the shortest reported until now. The simulation result shows that the extinction ratios for the TE and TM polarization are 13.5 and 16.6 dB at their respective output ports, and their insertion losses are 0.29 and 0.13 dB, respectively. Numerical simulations also show that the device offers a very large bandwidth () with large extinction ratio () and low insertion loss ().
© 2015 Optical Society of America
Full Article | PDF ArticleMore Like This
X. Sun, M. Z. Alam, J. S. Aitchison, and M. Mojahedi
Opt. Lett. 41(1) 163-166 (2016)
Bowen Bai, Lu Liu, and Zhiping Zhou
Opt. Lett. 42(22) 4752-4755 (2017)
Chih-Wei Hsu, Ting-Kai Chang, Jhen-Yu Chen, and Yung-Chen Cheng
Appl. Opt. 55(12) 3313-3318 (2016)