A Self-Calibrating Laser Ranging Method Based on ASE Broadband Random Signals and a Built-in Reference

In distance measurement, it is difficult to achieve both high precision and high dynamic response speed simultaneously. This paper proposes a laser ranging method based on amplified spontaneous emission (ASE) random signals. The method utilizes the truly random, broadband, and spectrally flat characteristics of ASE light sources. These features provide highly distinctive references for cross-correlation algorithms, enabling fast and high-precision time delay extraction. A “coaxial dual-peak” measurement scheme is introduced. It uses the internal end-face reflection signal as a built-in time delay reference. This allows self-contained absolute distance measurement without external calibration. Moreover, the cumulative gain of the cross-correlation algorithm effectively suppresses noise. It also significantly reduces the power requirement for the reference signal and avoids interference effects on measurement accuracy. Experimental results show that within a 2 m measurement range, the system achieves an absolute distance measurement standard deviation better than 30 μm with a single measurement time of only 100 ns. This research provides a reliable technical approach for real-time precision monitoring of extreme transient processes such as detonation and high-speed impact. It combines both high precision and ultra-fast dynamic response capability.