D. C. Truong, D. A. Vu and C. V. Hoang, Two Mode - (De)muxer Based on a Symmetric Y Junction Coupler, a \(2\times 2\) MMI Coupler and a Ridge Phase Shifter Using Silicon Waveguides for WDM Applications, Comm. Phys. 27 (2017) 327. DOI: https://doi.org/10.15625/0868-3166/27/4/10883.