A novel technique combining single soliton microcomb technology with optical phased arrays (OPA) could revolutionize parallel frequency-modulated continuous-wave (FMCW) LiDAR systems, enhancing their capabilities for three-dimensional imaging and sensing.
Modern applications of artificial intelligence, including autonomous driving and unmanned aerial vehicles (UAVs), demand efficient and high-speed data collection systems. The new research demonstrates how integrating silicon-based OPs with microcombs can meet these needs by enabling the parallel emission of multiple wavelengths for more effective LiDAR systems.
The researchers utilized wide waveguides beyond the single-mode region and incorporated effects of the bound state in the continuum to develop ultra-long optical grati ng antenna arrays. This innovative approach enhances the performance of LiDAR systems, which require precise wavelength emissions consistent with the Rayleigh criterion.
One of the team's significant findings showed the modulation bandwidth of the microcomb operates beyond the modulation region of single soliton microcombs, allowing for the creation of parallel FMCW signals with just one pump laser.
"The parallel frequency modulated multi-wavelength laser source with only one pump laser paves the way for all-solid-state LiDAR advances," the authors stated, underscoring the significance of their research.
LiDAR systems have evolved from their initial applications to become fundamental to the development of sophisticated AI technologies. Previous implementations utilized massive individual laser arrangements, significantly increasing costs and complicative assembly processes. The integration of microcomb technology allows for tens of distinct channels, resulting in fewer components and streamlined assembly.
The experimental setup included silicon nitride-based microcomb chips, which were pumped with continuous wave (CW) lasers to generate multiple comb frequencies. Following modulation by electro-optical modulators, the light was routed through the OPA for coherent detection, achieving three-dimensional imaging.
With regard to beam quality, the researchers have noted significant advancements. The measured beam divergence approached only 0.037°, which, together with the long optical grati ng constructed through advanced waveguide designs, achieved consistent spacing of 101.3 GHz. "This result is consistent with the comb tooth spacing and optimal Rayleigh criterion guidelines," the authors conveyed.
The integrated system was also characterized for its capability to perform high-speed ranging measurements. During testing, distance deviations were maintained at about 2.5 cm even within various experimental conditions, indicating high reliability and accuracy of this new LiDAR system.
Assessing the broader impacts of this advancement, the authors noted, "Different soliton comb states can all be used for coherent LiDAR applications in the future," hinting at future potential explorations of various configurations beyond those currently implemented.
Challenges remain, particularly concerning the need for balanced arrays of photodetectors and effective wavelength-division multiplexers. Nonetheless, the research suggests paths toward fully integrated systems capable of significant power efficiency and compactness.
With the convergence of these technologies, researchers are optimistic about the future implementation of all-solid-state LiDAR systems, enhancing the capabilities for applications such as autonomous vehicles and advanced UAV systems.
Given the rapid evolution of AI-dependent technologies and various sensing applications, this breakthrough holds substantial promise for the future of robotics and autonomous systems.
This innovative work explores not only the significant improvement of LiDAR systems but also the collaborative merging of optics and data transmission technologies, advocating for diverse future applications across numerous fields.