Femtosecond laser processing has emerged as a powerful technique for precision microfabrication inside optical fibers, enabling non-thermal refractive index modification and complex microstructure integration without compromising fiber integrity. Compared with conventional methods such as fusion tapering, chemical etching, and CO₂ laser processing, it offers unprecedented flexibility and accuracy for advanced photonic device development. This talk reviews our recent progress in femtosecond laser-engineered in-fiber microstructures and their applications in high-performance optical sensing and advanced fiber lasers. We present a series of novel microstructures, including Mach–Zehnder interferometers, helical and small-period long-period gratings, off-axis Bragg gratings, and hybrid cladding waveguides, which enable vector torsion, curvature, biochemical, gas, and high-temperature sensing with high sensitivity and multi-parameter discrimination. Furthermore, these microstructures serve as compact mode-lockers, random reflectors, and spectral filters, facilitating stable mode-locked lasers, random fiber lasers, and low-noise Raman lasers. This work demonstrates that femtosecond laser microstructure engineering provides a versatile pathway toward integrated, robust, and high-performance fiber-optic systems for both sensing and laser applications.

Dr Xuewen Shu is currently a professor working at the Wuhan National Laboratory for Optoelectronics (WNLO), Huazhong University of Science and Technology, China. Before he joined the WNLO, he spent about 13 years in UK working at Aston University and Indigo Photonics Ltd., as a Senior Research Fellow and a Senior Engineer, respectively. He has published over 300 papers in major international journals and conferences and also holds over 30 US, European and Chinese patents. He serves as an Associate Editor for IEEE Sensors Letters and a TPC member for several international conferences. He is a Fellow of the Optical Society of America (Optica) and Institute of Physics. His research interests include fiber gratings, optical fiber communications, fiber lasers and optical sensors.