Silicon Integrated Adiabatic Asymmetric Taper-Based Mode Multiplexer and Converter

Mode division multiplexing (MDM) has been widely studied in silicon photonic integrated circuits to increase data interconnection and processing capacity. Mode multiplexers and converters are important components in MDM systems. This letter proposes a novel asymmetric adiabatic taper-based device as the mode multiplexer and converter for TE0 and TE1 modes, enabling multiple modes to be transmitted through the same silicon waveguide (WG) to increase the capacity. The proposed device is simulated and fabricated using a 220 nm silicon-on-insulator platform. Experimental results show an insertion loss of lower than 0.44 dB over the entire measured wavelength range of 1520 nm - 1595 nm and an extinction ratio (ER) >20 dB. In addition, the device is very compact, occupying a size of only
$8\times 1.28\,\,\mu \text{m}^{2}$
. Therefore, the proposed device is promising in MDM-based silicon photonic integrations.