A SiN-Si Dual-layer Optical Phased Array with High Radiation Efficiency and Large Steering Range

We propose a 128-channel SiN-Si dual-layer optical phased array (OPA) chip based on SOI substrate. It combines the low loss characteristics of SiN with the excellent modulation characteristics of Si. Compared with a Si single-layer OPA chip, it avoids the problem of high waveguide loss in the case of high input optical power due to the strong nonlinear absorption effect of Si. Therefore, our double-layer OPA has lower overall waveguide loss and can achieve high output power, which is conducive to long-distance detection. When it works, the beam is emitted from the end faces of its waveguides, with a radiation efficiency over 94%. Since the center spacing of the waveguides in the antenna area is close to the sub-micron scale, a large scanning range of 100.4 degrees is achieved.