Extended-Range Frequency Domain Interferometric Ranging Based on Optical-Microwave Mapping Acquisition

An extended-range all-fiber frequency domain interferometric ranging based on optical-microwave mapping acquisition was proposed in this article. Theoretical analysis denotes that the frequency-domain interference signals can be mapped from the optical to microwave domain with equal periods through optical-electric conversion, which provides the possibility of significantly enhancing the measurement range of optical frequency domain interferometry by overcoming the limitations imposed by lower optical spectrum measurement resolution through high resolution microwave spectral acquisition. The proof-of-principle experiments had been performed to achieve an absolute distance measurement with a precision of 6.4 µm within range of 5.09 m. Compared with the existing optical domain interferometry ranging technology, the measurement range is improved by orders of magnitude while maintaining the micron-level ranging precision at minimal cost.