Fundamental analyses of fabrication-tolerant high-performance silicon mode (de)multiplexer

Mode-division multiplexing (MDM) has been extensively exploited to expand the capacity of chip-scale optical interconnects, whereas high-volume manufacturing of on-chip mode (de)multiplexers is still full of challenges. In this paper, we analyze the fabrication errors (sidewall, width, height) of silicon mode (de)multiplexer and present two cases of fabrication-tolerant high-performance silicon mode (de)multiplexer. The presented mode (de)multiplexer could eliminate the mode mismatch and mode hybridization caused by the fabrication errors. When sidewall errors are 0°, 5°, width errors are 0, ± 20, ± 30 nm, and height errors are 0, ± 10 nm, the designed fabrication-tolerant high-performance silicon mode (de)multiplexer can achieve low excess loss less than 2.5 dB and low inter-mode crosstalk less than -15 dB over a broad bandwidth from 1500 to 1600 nm. The obtained results provide an important guideline for designing fabrication-tolerant photonic integrated circuits on silicon platform, which could be applied to the prospective high-volume manufacturing and large-scale integration.