Large-Scale Silicon Photonic Circuits for Optical Phased Arrays

We review recent advances in integrated large-scale optical phased arrays. The design and fabrication of large-scale optical phased arrays using silicon photonic circuits are discussed from device designs including the directional couplers, thermooptic phase shifters, and optical nanoantennas, to system studies including phased array synthesis and noise analysis. By taking advantage of the well-developed silicon complementary metal-oxide-semiconductor (CMOS) fabrication technology, several large-scale integrated silicon photonic phased arrays are demonstrated, including two passive-phased arrays (64 x 64 and 32 x 32) with the ability to generate complex holographic images, an 8 x 8 active phased array for dynamic optical beamforming, and an 8 x 8 active antenna array with amplitude apodization. These optical phased array demonstrations, with up to 12 000 integrated optical elements, represent the largest and densest silicon photonic circuits demonstrated to date.