Polarization-insensitive ultra-short waveguide taper

Waveguide taper, a key component in the photonic integrated circuit (PIC), enables on-chip mode conversion, but large-footprint tapers are detrimental to the PIC, which desires compact and efficient devices. Polarization sensitivity also limits the tapers in the applications involving orthogonal modes. In this work, we design an efficient polarization-insensitive ultra-short MMI-based waveguide taper, through the mode spreading principle and the self-image principle. The proposed taper is 26.3 mu m long, one order of magnitude shorter than the standard linear taper. We fabricate the taper, and experimentally demonstrate that it exhibits a high transmission efficiency of similar to 70% and a wide 1 dB bandwidth of >54 nm, for both TE and TM polarizations. (C) 2021 Optical Society of America

Automated summary

In this study, we designed an efficient polarization-insensitive ultra-short MMI-based waveguide taper, which utilizes the mode spreading principle and the self-image principle to achieve high transmission efficiency and a wide bandwidth. Experimental results showed that the proposed taper has a transmission efficiency of approximately 70% and a bandwidth of over 54 nm for both TE and TM polarizations.