Efficient silicon integrated four-mode edge coupler for few-mode fiber coupling

• DOI: 10.3788/col202220.011302
• Publication Date: 2021-09-23T09:11:26Z
• Authors: Junbo Zhu; Haiyang Huang; Yingxuan Zhao; Yang Li; Zhen Sheng; Fuwan Gan
• Keywords: Splitter; Coupling loss; Mode coupling; Equilibrium mode distribution

Here, we designed a broadband, low loss, compact, and fabrication-tolerant silicon-based four-mode edge coupler, composed of 1×3 adiabatic mode-evolution counter-taper splitter triple-tip inverse taper. Based on mode conversion power splitting, the proposed structure can simultaneously realize efficient coupling from TE0, TM0, TE1, TM1 modes multimode silicon waveguides to linearly polarized (LP), LP01,x, LP01,y, LP11a,x, LP11a,y, in few-mode fiber. To best our knowledge, first scheme four LP coupling, which is fully compatible with standard fabrication process. The 3D finite-difference time-domain simulation results show that on-chip losses remain lower than 0.62 dB over 200 nm wavelength range, total are 4.1 dB, 5.1 2.1 2.9 for TE0-to-LP01,x, TM0-to-LP01,y, TE1-to-LP11a,x, TM1-to-LP11a,y, respectively. Good tolerance relaxed critical dimensions make coupler process commercial photonic foundries.