Design of multi-wavelength demultiplexing coupler based on DBS algorithm

Abstract

The optical coupler can couple the light from the fiber into the waveguide, and the wavelength demultiplexer can split light into different wavelengths. Both devices play a very important role in optical chips, and combing them together can further reduce the chip footprint and improve the operating efficiency. In this work, based on the direct-binary-search (DBS) inverse design algorithm, we design two metamaterial couplers that can realize multi-wavelength demultiplexing. The two devices are based on silicon on insulator (SOI) and cover an ultra-compact footprint of 3.6 μm × 3.6 μm. The first device can couple and split 1310 nm and 1550 nm light into two separate waveguides with the coupling efficiencies of 0.26 and 0.27, respectively. The second device can couple and split 1310 nm ,1490 nm and 1550 nm light into three separate waveguides with the coupling efficiencies of 0.25, 0.2 and 0.23，respectively. The large number of guide-mode resonances in the device leads to this effect. The two couplers, especially for the three-wavelength demultiplexing coupler, can be used as splitter for monolithically silicon integrated transceivers at the main optical fiber communication wavelength of 1310 nm, 1490 nm and 1550 nm, which potentially meets the low-cost and ultra-compact requirements for future passive optical networks.

Compact multi-functional device for optical communication systems

“…By applying a gradient-based inverse design algorithm, researchers proposed tunable on-chip fundamental mode to higher-order modes converter [6]. Power splitters and mode converters have also been proposed by using heuristic-based algorithms [7,8]. Following these studies, researchers started to investigate the possibility of devices that can carry out multiple operations with a single device.…”