Ultra-Compact Sb2S3-Silicon Hybrid Integrated Arbitrarily Cascaded Tunable Mode Converter

Abstract

Orthogonal modes are utilized to broaden the bandwidth of the communication systems and mode-order converter is a pivotal components component for mode-division-multiplexing systems. To provide an alternative solution which is both robust to the wavelength variation and has an ultracompact footprint, we propose a new concept of mode converter in this paper. We design two kinds of prototypes in which Sb₂S₃ are put above the silicon waveguides and embedded into the waveguides. The footprints of these devices are 2.21 μm × 7.06 μm and 1.04 μm × 2.73 μm, respectively. The cascaded gap can be compressed to 0.2 μm almost no additional loss is introduced. The simulation result shows that the insertion losses of device are lower than 1.9 dB and 1.3 dB, and the signal-to-noise ratios are larger than 11.2 dB and 10.1 dB throughout the wavelength of 1500–1600 nm. Moreover, the method to tune the mode-orders could also be applied to a series of dynamic devices utilizing modes.