FOCAL PLANE ARRAY AND LIDAR DEVICE INCLUDING THE SAME

Smart overview of the Invention

The focal plane array (FPA) discussed is designed to enhance LiDAR systems by incorporating a unique grating coupler structure. This array consists of multiple pixels, each capable of transmitting a light beam towards a target and receiving the reflected beam. The design includes a transmission grating coupler, a reception grating coupler, and a geometric phase (GP) optical device, which together facilitate efficient light path splitting and minimize light loss.

Technological Context

LiDAR technology, particularly when based on silicon photonics, can be categorized into various types such as direct time of flight (DTOF), indirect time of flight (ITOF), and frequency-modulated continuous wave (FMCW). The FMCW method stands out for its high range and velocity resolution, even in environments with ambient noise, making it suitable for silicon photonics-based LiDAR systems. The FPA method, known for its simplicity and effective side mode suppression, is particularly advantageous when paired with the FMCW approach.

Functional Components

Each pixel in the FPA is equipped with a transmission grating coupler and a reception grating coupler. The GP optical device, which can be a lens, deflector, or deflector lens, plays a crucial role by modulating the polarization direction of the light beams. This modulation involves changing the polarization from left-circular to right-circular or vice versa, ensuring optimal interaction with the target and efficient reception of the reflected beam.

Structural Variations

Various embodiments of the FPA include different configurations of the GP optical device and grating couplers. For instance, the transmission grating coupler may be larger than the reception grating coupler or vice versa. Additionally, the inclusion of a quarter wave plate is noted in some designs, providing further modulation capabilities between the transmission and reception grating couplers and the GP optical device.

Material and Design Considerations

The GP optical device is constructed using either liquid crystal or nanostructures, enhancing its ability to modulate light efficiently. The FPA also includes a buried oxide (BOX) layer and a cladding layer, which together support the structural integrity and functionality of the array. The arrangement of these components ensures that the FPA can effectively manage light paths and polarization states to optimize LiDAR performance.