Low Loss SOI Waveguides and MMIs at the MIR Wavelength of $2~\mu$ m

In this letter, we demonstrate high-performance waveguides and MMIs on an SOI platform at the fixed wavelength of 2 μm. The propagation loss demonstrated by the waveguides and the insertion loss of the MMIs are as low as 1 dB/cm and 0.29 dB, respectively, with TE polarization. To the best of our knowledge, this is the lowest loss for Si rib waveguides reported at a wavelength of 2 μm.