Characterization of Polymer Fiber Bragg Grating With Ultrafast Laser Micromachining

Abstract

Abstract-We report that the main photosensitive mechanism of poly(methyl methacrylate)-based optical fiber Bragg grating (POFBG) under ultraviolet laser micromachining is a complex process of both photodegradation and negative thermo-optic effect. We found experimentally the unique characteristics of Bragg resonances splitting and reunion during laser micromachining process providing evidence of photodegradation while the mean refractive index change of POFBG was measured to be negative confirming further photodegradation of polymer fiber. The thermal-induced refractive index change of POFBG was also observed by recording the Bragg wavelength shift. Furthermore the dynamic thermal response of the micromachined-POFBG was demonstrated under constant humidity, showing a linear and negative response of around -47.1 pm/°C.

Surface ablation and threshold determination of AlCu4SiMg aluminum alloy in picosecond pulsed laser micromachining

“…Recently, the interaction between the ultrafast pulsed laser and the material surface has become a research hotspot of significant attention due to the rapid development of laser processing technologies [1][2][3][4][5]. Ultrafast pulsed laser ablation exhibits many unique processing advantages, such as high ablation precision and efficiency, more controllable, minimal processing size, and almost no thermal damage and boundary effect, by virtue of its extremely short pulse duration and very high peak energy [4][5][6].…”