Electro-Optic beamforming in seamless wireless-to-photonic receiver arrays
This paper develops the theory behind electro-optic beamforming in seamless wireless-to-photonic receiver arrays. We show that the modulated phase of a traveling optical carrier signal in a wireless-to-photonic receiver array is governed by the direction of wireless reception, forming the basis for seamless electro-optic beamforming. We define a parameter referred to as the electro-optic array factor, which essentially governs the shape of the resultant electro-optic beam pattern. The analytical and physical interpretations behind maximas and nulls in seamless electro-optic beamforming are presented, and the design equations for controlling the electro-optic beam pattern are derived. In addition, the inadvertent nature of the presence of secondary electro-optic maximas is highlighted. Two distinct configurations of seamless electro-optic beamforming i.e. parallel-k and anti-parallel-k modes are introduced and compared. Further, a seamless electro-optic beamforming configuration that enables spatial-to-wavelength division multiplexing is proposed towards the end of the paper. The core theoretical contributions presented in this paper are crucial for further investigation and practical realization of seamless electro-optic beamforming in the next-generation communication systems like B5G and 6G.