Optical ranging system based on multiple pulse train interference using soliton microcomb

Abstract

The multiple pulse train interference (MPTI) ranging system takes advantage of the high accuracy and absolute length measurement capability, but traditional scheme has a large measurement dead zone. In this Letter, we propose a MPTI ranging scheme based on chip-based soliton microcomb to achieve high-precision but no dead-zone measurement. The measurement optical path is improved to solve the problem of cross correlation interference fringe overlap, and a peak fitting algorithm is employed to further improve the measurement accuracy of the system. Using a commercial He–Ne interferometer, a 384 nm precision is obtained in 1.5 m distance measurements. Advantages of the simple optical path, high precision, and no measurement dead zone are expected to realize on-chip integration and provide a solution for precision measurement.

Nonmeasurable Range Elimination of Dispersive Interferometry

“…In addition, white light sources usually have lower coherence, which is also an important factor limiting the DPI measurement range. − In order to expand the DPI measurement range, optical frequency combs (OFCs), as a revolutionary light source with high coherence and ultrawide spectral range, have become ideal light sources for DPI ranging. − In order to eliminate the measurement dead zone, optically down-sampled (frequency selected) methods have been proposed and implemented using Fabry-perot (FP) cavity or virtually imaged phased array (VIPA). , To further enhance the measurement distance and system integration, on-chip soliton microcombs (SMCs) are employed as the light sources for measurement. Their allure stems from their exceptional coherence and ultrahigh repetition rate, which guarantee the system’s ability to perform measurements free of dead zones, given that the spacing of their comb teeth surpasses the resolution of the spectral acquisition equipment. − When amalgamated with other coarse ranging methodologies and homodyne interference techniques, DPI ranging systems can achieve a measurement precision at the nanometer level and a measurement range extending to kilometers. , …”