Femtosecond laser direct writing of Fiber Bragg Grating with high-speed and high-resolution scanning technique

Abstract

We employed two fabrication methods, a laser scanning system and a phase mask, to produce Fiber Bragg Gratings (FBGs). A micro-scanning adapter was used to enable high-speed and high-resolution laser focusing inside the optical fiber via a scanner and an objective lens. By continuously moving the fiber-fixed stage while adjusting the scanner repetition speed, micropatterns with various periods were generated. This approach allowed for the detection of FBG signals at multiple wavelengths. Laser direct writing, utilizing a high-speed and high-resolution laser scanning system, facilitated FBG production without the need to remove the fiber coating. This method provided a straightforward way to control the FBG wavelength, signal intensity, and bandwidth by adjusting the scanner and stage movement speeds. The use of femtosecond lasers for FBG fabrication offers the additional advantage of reduced material dependence, enabling FBG production in various optical fibers without requiring additional processing steps compared to conventional methods. © 2024 The Authors