Multi-Dimensional Optical Fiber Sensing Enabled by Digital Coherent Optical Technologies

Optical fiber sensing (OFS) systems can be used to accurately measure temperature, strain, pressure, and other physical parameters by detecting the change in the field of lightwave. As they are used in more application areas, a new type of OFS with the ability of providing multi-dimensional, highly sensitive, ultra-fine, and real-time measurement is necessary. This is possible with the application of digital coherent optical technologies in the OFS systems. In this paper, we show that many aspects of OFS systems can be replaced or enhanced by digital coherent optical technologies. For example, digital optical frequency comb (DOFC) can replace the sweeping laser source, and the digital coherent optical receiver can replace the direct detection receiver to enable simultaneous detection of all the dimensions of lightwave. Based on these techniques, we present our research progresses on OFS with multi-dimensional, real-time, ultra-fine spectral analysis, and single-shot Brillouin optical time-domain analysis based DOFC for distributed OFS. We show that the OFS systems can be bought to a whole new level with the capabilities of real-time time-frequency analysis, ultra-fine spectral resolution, and ultra-low sensitivity. Opportunities and challenges of using digital coherent optical technologies in OFS systems are also discussed.