Long period fibre gratings inscribed by sinusoidal intensity modulated femtosecond laser. (14th December 2021)

• Record Type: Journal Article
• Authors: Zhao, Xiaofan; Li, Hongye; Rao, Binyu; Wang, Meng; Wu, Baiyi; Wang, Zefeng
• Is Part Of: Journal of optics. Volume 24:Number 1(2022)
• Publication Date: 2021-12-14
• Subjects: long period fibre gratings -- femtosecond laser -- direct inscription -- low insertion loss; Optics -- Periodicals; 535.05
• DOI: 10.1088/2040-8986/ac3c30
• Languages: English
• ISSNs: 2040-8978

Abstract

Abstract: To the best of our knowledge, this is the first study to propose and verify a novel and simple direct inscription method for long-period fibre gratings (LPFGs) with an arbitrary grating period using a sinusoidal intensity modulated femtosecond laser. This method induces a sine refractive index modulation, which makes the LPFGs have no higher-order harmonic resonance that exists in the normal square-wave modulation method. This is beneficial for reducing the insertion loss of the LPFGs and optimising the transmission spectrum. Using this method, we also conveniently realise the inscription of superimposed, apodised, and chirped LPFGs. This work presents a simple but effective inscription scheme for various types of LPFGs using a femtosecond laser.