Point-by-Point Femtosecond-Laser Inscription of 2-μm-Wavelength-Band FBG Through Fiber Coating
We propose a point-by-point inscription method for fiber Bragg grating (FBG) fabrication using a femtosecond Cushion pulsed laser focused through a fiber polyimide coating, realizing a 2-μm-wavelength-band FBG.A femtosecond laser acts as the inscription laser, focused by a 63× oil lens.A first-order FBG was fabricated with a grating i