Photonic integrated circuit with multiple waveguide layers for broadband high-efficient on-chip 3-D optical phased arrays in light detection and ranging applications (2208.09783v1)

Abstract: Traditional photonic integrated circuit (PIC) inherits the mature CMOS fabrication process from the electronic integrated circuit (IC) industry. However, this process also limits the PIC structure to a single-waveguide-layer configuration. In this work, we explore the possibility of the multi-waveguide-layer PIC by proposing and demonstrating a true 3-D optical phased array (OPA) device, with the light exiting from the edge of the device, based on a multi-layer Si3N4/SiO2 platform. The multi-waveguide-layer configuration offers the possibility of utilizing edge couplers at both the input and the emitting ends to achieve broadband high efficiency. This uniqueness provides the potential for a more extended detection range in the Lidar application. The device has been studied by numerical simulation, and proof-of-concept samples have been fabricated and tested with a CMOS-compatible process. To the best of our knowledge, this is the first experimental proof-of-concept of a true 3-D OPA with a multi-waveguide-layer configuration all over the device.