Light, detection and ranging (LiDAR), has been emerging as a powerful tool for applications with accurate and reliable perception requirements, e.g., autonomous driving which needs a combination of long-range and high spatial resolution together with a real-time performance. Processing the raw LiDAR data, which is a large-dimensional unstructured 3D point cloud, is computationally costly due to the nature of the algorithms used for processing the point clouds. In particular, the neural networks employed for LiDAR data processing comprise several layers, for each of which multiplications of matrices with large sizes need to be performed. In this case, graphics processing units (GPUs) cannot be used as real-time standalone devices for hardware acceleration because they have high execution time due to their dependency on a central processing unit (CPU) for data offloading and scheduling the execution of the algorithms used to process point clouds. To address the aforementioned challenges, we propose an efficient co-design of an analog neural network (ANN) and a hybrid CMOS-Photonics platform for LiDAR systems. The proposed architecture exploits the high bandwidth and low latency of optical computation to significantly improve the computational efficiency. In particular, in our proposed architecture, a CMOS control chip integrated with a photonic broadcast-and-weight architecture is interfaced with LiDAR to perform real-time data processing and high-dimensional matrix multiplications. Moreover, by processing the raw LiDAR data in the analog domain, the proposed hybrid electro-optic computing platform minimizes the number of data converters in LiDAR systems.
In this paper, we present a new compact and versatile spectrometer system operating at 1.55 μm for research and industrial application. The system is capable of testing solid, powder, thin film, gas, and liquid samples for material sensing and characterization applications. A high efficient system with bandwidth up to 1.2 THz is realized by using a fiber coupled terahertz chip packaging technology. The key components are the fiber-coupled THz transmitter and receiver modules, where the laser beam is directly coupled to the THz chip using optical fibers to provide stable and movable transmitter and receiver heads. The antennas are excited by 100 fs optical pulses at 1550 nm telecom wavelength and average power of 10mW. As femtosecond pulses are required on the antenna, the linear dispersion and nonlinear effect resulting from the propagation of the high power optical pulse along the fiber are taken into account and compensated using dispersion compensation fiber. A fast scan optical delay module is employed to realize real-time THz signal and spectrum measurement. The optical delay module also has a long delay scan unit to allow the user to adjust the distance between the transmitter and receiver heads by up to 1m to use the system for characterization of materials in different industrial applications.
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