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ABSTRACT Existing light detection and ranging (LiDAR) systems, such as time‐of‐flight (ToF) and frequency‐modulated continuous‐wave (FMCW) architectures, face intrinsic trade‐offs among acquisition speed, measurement range, and computational complexity. ToF systems offer fast acquisition but are sensitive to ambient light and suffer from limited range fidelity. FMCW systems provide high signal‐to‐noise ratios via interferometric detection but require long‐coherence‐length lasers and fast Fourier transform (FFT)‐based processing. We present a time‐domain interferometric LiDAR architecture that overcomes these limitations by directly encoding distance into time‐domain interference signals. The system integrates a stretched‐pulse mode‐locked swept source with a k‐linear chirped fiber Bragg grating in a time‐stretched interferometer, enabling high‐speed, high‐precision ranging without FFT or long‐coherence‐length sources. Operating at 5.0016 MHz with a coherence length of a few millimeters, the system measures distances up to 12 m—approximately 10 000 times the effective coherence length—with 9.5 mm mean precision and 13 mm accuracy. High‐speed validation is demonstrated by resolving 10 and 5 kHz binary distance transitions using a rotating optical chopper. Additionally, 3D imaging between 6 and 12 m is achieved using a galvo‐mirror scanner, with clearly separated depth planes and millimeter‐level repeatability. These results establish a compact, scalable, and computationally efficient LiDAR platform for real‐time, high‐performance ranging.
Jung et al. (Tue,) studied this question.