High-efficiency conversion from waveguide mode to an on-chip beam using a metamaterial engineered Bragg deflector

Diffraction gratings that redirect light propagating in a channel waveguide to an on-chip slab are emerging as important building blocks in integrated photonics. Such distributed Bragg deflectors enable precise shaping of slab confined beams for a variety of applications, including wavelength multiplexing, optical phased array feeding, and coupling interfaces for on-chip point-to-point communications. However, these deflectors suffer from significant losses caused by off-chip radiation. In this Letter, we show, for the first time, to the best of our knowledge, that off-chip radiation can be dramatically reduced by using the single-beam phase matching condition and subwavelength metamaterial refractive index engineering. We present a deflector design with losses below 0.3 dB, opening a path toward new applications of distributed Bragg deflectors in integrated photonics. (C) 2021 Optical Society of America

Automated summary

Diffraction gratings that redirect light in a channel waveguide to an on-chip slab are becoming important in integrated photonics. By utilizing single-beam phase matching and subwavelength metamaterial refractive index engineering, off-chip radiation can be significantly reduced, allowing for new applications of distributed Bragg deflectors with minimal losses.