The Integrated Optical Phased Array on Silicon Photonics

The new era of intelligence and informatization are coming with the urgent need for advanced sensing technology in the applications such as the autonomous vehicles, intelligent environmental monitoring, smart office and living. LiDAR, short for light detection and ranging, is a distant measuring and sensing technology widely adopted in these scenarios. Optical phased array (OPA), which is one of the beam steering schemes in the LiDAR system, stands out due to its miniaturization and solid state operation ability. It has attracted intensive researching interest among both the academy and industry. Pioneering work are being carried out to develop an OPA chip with large aperture size, large field of view (FOV), low side lobe level (SLL), fast operation speed and high degree of integration. It is considered by the community as the next generation solution for the beam steering component in the LiDAR system. In this thesis, we have successfully demonstrated the integrated OPA chip on silicon photonics based on a fundamentally new scheme, the slab grating OPA. The
main effort has been spent on the theoretical work, the fabrication and characterization of the slab grating OPA device from scratch. The first proof-ofconcept of the device was demonstrated on a 64-channel and half-wavelength-pitch OPA silicon chip controlled by Digital Analog Converters (DACs). The FOV and the SLL are both measured as the record best to our knowledge when this thesis was written. The second demonstration was done on a 1000-channel and half-wavelengthpitch OPA silicon chip controlled by a Field Programmable Gate Array (FPGA) board. The 1000-channel OPA has proven the feasibility of our proposed scheme in a large scale. Even though the performance regarding the tuning speed and SLL has seen some degradation, it can be improved for better performance. From the fundamental research point of view, the exploration of the new slab
grating based scheme in this thesis is valuable for overcoming the fundamental limitation of FOV in integrated OPA. From the practical application point of view, the OPA device with 180° FOV can potentially provide a sensor solution for LiDAR with zero blind spot.