Low-loss off-axis curved waveguide grating demultiplexer

Current optical communication systems rely on the use of wavelength division multiplexing (WDM) to keep up with the increasing data rate requirements. The wavelength demultiplexer is the key component to implement WDM systems. In this Letter, we design and experimentally demonstrate a demultiplexer based on a curved grating waveguide geometry that separates eight channels with a spacing of 10 nm(1249 GHz) around the central wavelength of 1550 nm. The fabricated device shows very low insertion loss (similar to 1 dB) and a crosstalk (XT) below -25 dB. This device leverages metamaterial index engineering to implement the lateral cladding on one side of the waveguide. This makes it possible to design a waveguide grating with highly directional lateral emission by operating in a regime where diffraction into the silica upper cladding is frustrated, thus suppressing losses due to off-chip radiation. (C) 2021 Optical Society of America.

Automated summary

The study introduces a demultiplexer based on a curved grating waveguide structure that separates eight channels around the central wavelength of 1550 nm with a spacing of 10 nm. The fabricated device exhibits very low insertion loss and crosstalk below -25 dB, showcasing the potential of metamaterial index engineering in achieving highly directional lateral emission in waveguide grating design.