Compact multi-functional device for optical communication systems

Current optical communication systems slowly fall behind the data-carrying capacity needs of the modern world. These systems mostly implement single-mode fibers, which is one of the main reasons why such networks are falling behind. To overcome this issue and increase data rate, wavelength-division multiplexing (WDM) and space-division multiplexing (SDM) arise as very appealing solutions. Both of them utilize components such as demultiplexers, multiplexers, amplifiers, single or multimode fibers, etc. While improving the performance of optical communication systems, it is also important to keep them compact or to use fewer components. To serve these needs, we propose a multipurpose device that can carry our mode conversion and wavelength demultiplexing simultaneously. The proposed device is designed on a Silicon-on-Insulator (SOI) platform by using topology optimization (TO) and ensure fabrication possibility, we have set the minimum feature size to 70 nm. Our device has the dimensions of 4 μm by 3 μm having a thickness of 220 nm, and can convert TE1 mode to TE0 mode at output ports. The upper port is set to transmit the wavelength range of 1.52 μm – 1.56 μm whereas the lower waveguide is set to allow 1.58 μm – 1.62 μm band to pass through. In addition, our device yields a high conversion efficiency around 90%. We believe that our device can pave the way for designing efficient multifunctional devices to be used in future optical communication systems.