Patented Technology First Released in China

At the 3rd National Photonic Technology Forum held in Guangzhou from 31st of March to 3rd of April 2023, Professor Wang Yiping's team from Shenzhen University and Shenzhen Photonic Sensing Technology Co. Ltd., released for the first time in China, a fully automatic femtosecond laser based large-scale fiber grating array fabrication technology and products.

This advanced technology enables highly efficient and fully automated preparation of large-scale series/parallel integrated fiber grating (including weak reflection point) arrays at the km level in single-core and multi-core optical fibers. The advantages include direct writing through a layer of coating, no mask, no hydrogen loading, no secondary coating, and fiber spool-to-spool processing. It features fully automatic control of grating preparation processes such as fiber movement, clamping, fiber take-in, fiber take-out, fiber core alignment, laser focusing and exposure. Optical fibers containing fabricated fiber grating arrays retain the original tensile strength of the pristine fiber, and are resistant to high temperatures with excellent long-term stability.

The grating wavelength of the large-scale weak-reflection fiber grating array unveiled onsite is 1550 nm, minimum grating length is <0.5 mm, minimum grating pitch is <0.5 mm, minimum reflectivity is <1/100000, grating quantity is >10,000, extinction ratio is 15 dB. 

Parameters such as grating wavelength, grating reflectivity, grating pitch, and grating quantity can be customized on demand. Large-scale fiber grating arrays have important and a broad range of applications in distributed fiber-optic sensing for oil & gas exploration, perimeter security, bridges and dams monitoring, and aerospace fields. They can vastly improve measurement accuracy, sensing distance, spatial resolution, and other key indicators of technologies such as DAS, DTS and OFDR. It is an important "booster" of distributed fiber-optic sensing technology.