Ultra-compact dual-wavelength-dual-mode (de)multiplexer utilizing topology optimization

A novel ultra-compact dual-wavelength-dual-mode (de)multiplexer is demonstrated for highly integrated on-chip hybrid mode and wavelength division multiplexing systems. This device is designed on Silicon on Insulator (SOI) and optimized using an inverse design method, which named topology optimization. The proposed device occupied a footprint of only 4.8 × 4.8 µm2, which is the smallest device implementing hybrid multiplexing technology as is known to all. Then, the device enables signal (de)multiplexing of modes TE0 and TE1 at 1525 nm and 1575 nm. Besides, the simulated insertion loss and crosstalk were less than 0.2918 dB and –17.23 dB for each channel, respectively. Furthermore, this scheme could also be expanded to include more channels.