The advancement of the optical fiber sensing (OFS) technology is strongly linked to the development of light sources, while lasers play a crucial role in determining the performances of OFS systems for diverse sensing applications. Over the past 15 years, the OFS group at the University of Electronic Science and Technology of China (UESTC) has focused on the OFS with various light sources. Here, we review the history of the OFS advancement at UESTC and conduct an in-depth examination of the sensing strategies involving advanced light sources and cutting-edge sensors. By employing single-frequency lasers (SFLs), multi-frequency lasers (MFLs), and optical frequency combs (OFCs) across various sensing scenarios, the research team reports a number of novel OFS devices and systems, and showcases their sensing capabilities from point sensors to distributed sensing, and sensor networks. We highlight the role of novel light sources, particularly integrated OFCs, in enhancing the OFS. Our findings show that OFCs, with outstanding merits of the ultrahigh coherence, broad bandwidth, ultrafast detectability, and multi-channel parallelism, can significantly improve the capabilities and performances of the OFS used for detecting both physical and biochemical parameters. To conclude, we provide a systematic overview of the OFS advancement at UESTC, with SFLs/MFLs, as well as OFCs, and discuss the technical challenges and prospects, as well as potential developments of the OFC empowered the OFS. Also, a roadmap is proposed for transitioning the OFCs-based OFS technology from laboratory settings to practical applications.

Whispering gallery mode microresonators significantly enhance light-matter interactions, making them ideal platforms for a wide range of applications, including lasers, nonlinear converters, modulators, and sensors. Recently, the integration of sensitive materials such as graphene within optical microcavities has overcome the inert nature of the traditional optical microresonators, paving the way for highly sensitive biochemical detection. However, challenges such as Q factor deterioration, complex mode analysis, and demanding operation processes remain, resulting in intricate experimental setups, high excitation thresholds, and issues with device reliability and portability. Besides, the selectivity in the sensing process is also a challenge which relates to the material property. In this work, we present a gas sensor by combining functionalized graphene with a microrod resonator, addressing these challenges with the low threshold, simple structure, easy operation, high sensitivity, and switchable selectivity. By monitoring the shift of the resonant mode caused by the adsorption of gas molecules, we achieve the 1.1 ppb level detection of NH₃ and CO₂ in the P-doped graphene based microresonator and demonstrate 4 ppb level detection of NO₂ with high selectivity by changing the doping state of graphene from P to N. Our approach showcases the advantages of low cost, high sensitivity, and switchable selectivity, providing a promising solution for flexible and high-performance chemical sensing systems.

Single atomically thick graphene, with unique structural flexibility, surface sensitivity, and effective light-mater interaction, has shown exceptional advances in optoelectronics. It opens a door for diverse functionalized photonic devices, ranging from passive polarizers to active lasers and parametric oscillators. Among them, graphene-fiber biochemical sensors combine the merits of both graphene and fiber structures, demonstrating impressively high performances, such as single-molecule detectability and fast responsibility. These graphene-fiber biochemical sensors can offer tools in various applications, such as gas tracing, chemical analysis, and medical testing. In this paper, we review the emerging graphene-fiber biochemical sensors comprehensively, including the sensing principles, device fabrications, systematic implementations, and advanced applications. Finally, we summarize the state-of-the-art graphene-fiber biochemical sensors and put forward our outlooks on the development in the future.