Secure FMCW LiDAR Ranging With an Electro-Optical Synthesizer at 5000 Measurements/s

Frequency-modulated continuous wave (FMCW) LiDAR offers a significant advantage over FMCW RADAR due to its superior lateral resolution, achieving more than a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1000\times $ </tex-math></inline-formula> improvement. However, laser nonlinearities require the use of electro-optical phase-locked loops (EO PLLs), and conventional EO PLL-based FMCW LiDAR systems are susceptible to spoofing attacks. To address this vulnerability, this letter introduces an electro-optical (EO) synthesizer designed to generate FMCW signals with randomly varying chirp rates per frame. The synthesizer incorporates an on-chip SRAM-based physically unclonable function (PUF) fabricated in 180-nm RF CMOS, which generates a device-specific random key to enhance the security of FMCW LiDAR against spoofing attacks. The synthesizer supports four programmable chirp rates: from 8.5 to 12 GHz/ms with a chirp period of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$600~\mu $ </tex-math></inline-formula>s, and from 12.75 to 18 GHz/ms with a chirp period of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$200~\mu $ </tex-math></inline-formula>s, resulting in a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$5\times $ </tex-math></inline-formula> increase in generated cloud points compared to existing long-range EO PLL-based FMCW LiDAR systems.