With the advancement of artificial intelligence and automation technologies, intelligent devices that require enhanced agility and adaptability to varying environments have become more critical. The need for these systems to achieve rapid and precise spatial perception has become increasingly prominent. Among such technologies, light detection and ranging (LiDAR) technology has emerged as a revolutionary advancement in the field of autonomous vehicles, remote sensing and industrial automation. By providing high-resolution three-dimensional spatial information, LiDAR has significantly enhanced the precision and reliability of various applications. As a highly integrated optical system, LiDAR exhibits diverse pathways based on different principles. Each type of LiDAR imposes unique demands on the performance specifications of core optoelectronic devices including light sources, modulators, photodetectors, and scanning mechanisms. For the entire system to achieve optimal technological metrics, including enhancing range measurement capability, improving spatial resolution, lowering energy consumption and extending battery life, increasing compactness, and ensuring robust immunity to environmental interference, among other improvements, it is essential to judiciously integrate the various core components tailored to their respective strengths and weaknesses. Therefore, gaining a comprehensive understanding of the performance indicators, advantages, limitations, development trends, and technical routes of each constituent photonic device within the LiDAR system is crucial for advancing its design, research, and manufacturing processes. This knowledge base will serve as a foundation for addressing future challenges in LiDAR technology.

This review systematically summarizes recent advancements in these devices and components. First, the performance requirements of light sources for different ranging principles are analyzed, with a focus on the characteristics and applicability of distributed feedback lasers (DFB) and vertical-cavity surface-emitting lasers (VCSEL). The article summarizes their characteristics, application scenarios, and recent advancements in these technologies within LiDAR systems. Second, we elaborate on modulation technologies, including DFB laser internal modulation, electro-optical modulation, acousto-optic/piezoelectric modulation, and spatial-domain modulation. The implementation principles and research progress of these modulation methods are explained, along with the key technical indicators they concern and their impact on the overall performance of the LiDAR system. Third, the progress of three major photodetection technologies—avalanche photodiodes (APD), single-photon avalanche diodes (SPAD), and superconducting nanowire single-photon detectors (SNSPD)—is reviewed. We also analyze the potential advantages and challenges when integrating these detector technologies into a complete LiDAR system, considering their compatibility with other core components and practical operating environments. Finally, various beam scanning mechanisms, such as flash LiDAR, microelectromechanical systems (MEMS) LiDAR, optical phased array (OPA) LiDAR, focal plane array (FPA) LiDAR, and dispersive scanning techniques, are discussed. This review highlights the diverse technological approaches employed in LiDAR systems and the distinct performance requirements of their key components. By optimizing the selection of components and tailoring their performance to specific application scenarios and ranging principles, the overall system performance can be significantly enhanced. The article also highlights how these efforts can enhance system performance while also boosting the capabilities of individual devices. This review provides a comprehensive overview of the progress, challenges, and future directions in LiDAR technologies, serving as a valuable reference for advancing research and development in this field.

The review introduces VCSEL lasers based on FMCW ranging and various types of lasers based on ToF ranging. Each has its unique advantages and is suitable for different application scenarios. The choice and optimization of these light sources directly affect the measurement accuracy, response speed, and performance of the LiDAR system.

The review delves into an extensive discussion of the LiDAR modulator and its modulation methods. As a critical component responsible for signal shaping in the LiDAR system, the modulator affects the stability and reliability of the received signal, regardless of whether it is based on FMCW ranging or ToF ranging. The introduction of intra-cavity modulation, electro-optic modulation, piezoelectric/photovoltaic acousto-optic modulation, and spatial domain modulation in this paper provides flexible and efficient means for signal modulation in LiDAR systems, thereby improving their interference resistance capabilities and measurement accuracy.

The paper also focuses on the research progress of various types of detectors, such as APD, SPAD, and SNSPD, which serve as receivers. The performance of the detector determines the sensitivity and detection range of the LiDAR system under weak light conditions. With advancements in detector technology, the detection ability of the LiDAR in low-light environments has been significantly enhanced, providing strong support for applications such as autonomous driving, drone navigation, and topographic mapping. This paper also summarizes the application of different scanning methods in LiDAR systems. These scanning technologies not only improve the scanning speed and resolution of the LiDAR systems but also expand their application scope, showcasing significant potential in fields such as autonomous vehicles, unmanned aerial vehicles, and terrain surveys.

This paper contributes to a better comprehension of LiDAR technology and offers valuable insights into its continued advancement and practical applications. With the advancements in component performance and emerging technologies, LiDAR systems are poised to assume more critical roles in unmanned platforms, thereby making substantial contributions to the intelligent development and evolution of human society.