Design of integrated optical beam steerer based on cascaded ring resonator

Free-space beam steering plays an important role in ultrafast switching and scanning applications. This paper proposes an alternative method to realize two-dimensional large-angle beam steering for single wavelength light on silicon photonics platform. The steerer consists of an electrically controlled I×N cascaded add-drop ring resonator and N off-chip coupler arrays. Each output of the resonator connects with one off-chip coupler array to emit light to free space at a certain direction. Single wavelength light coupled in the input bus waveguide of the cascaded ring resonator can be switched among these N outputs by means of tuning the refractive index of the cascaded rings electrically and then be emitted to different directions in far field, which behaves as beam steering apparently. The steering can be one- or two-dimension, depending on the arrangement of these TV off-chip coupler arrays on the chip. Moreover, the proposed steerer can be combined with the conventional optical phased array for more precisely beam steering.