- This event has passed.
DTU Lys Colloquia: Prof. Kyriacos Kalli
November 21, 2016 @ 9:15 am - 10:15 am
Title: Femtosecond Laser Processing of Optical Fibres
Associate Professor, Department Chair
Department of Electrical Engineering, Computer Engineering and Informatics
CYPRUS UNIVERSITY OF TECHNOLOGY
Femtosecond (fs) lasers are well suited for high-resolution inscription and micromachining in transparent materials of all types. Silica and low loss polymer optical fibres can be readily modified using fs-laser, direct-write methods that offer great flexibility and are often simple and single-step processes. The short temporal duration of fs-laser pulses lead to intensity-dependent, non-linear absorption processes for moderate average laser powers. Multi-photon absorption and avalanche ionization can occur in the focal volume, leading to refractive index changes and/or micro voids; this selective material modification allows for the flexible patterning and prototyping of micro- and nano-structures. We present new opportunities in fibre device design using fs lasers, by inscribing fibre Bragg grating (FBG) structures in optical fibre cores, integrated circuits in the fibre cladding, and Fourier optic and non-diffracting beam devices on the end face of optical fibres. FBGs in multi-core and polymer optical fibres have many applications related to high strain recovery and shape sensing, whereas taking advantage of the fibre cladding allows for new, self-contained optical fibre devices, and finally one may realise 1-D and 2-D grating structures written across the fibre end face, along with Bessel, Airy and vortex beam generators, all using single mode fibres. Moreover, we present gratings in semiconductor-core glass fibres that have emerged recently as an interesting alternative to planar silicon for a variety of optoelectronic applications; this as an important step towards in-fibre photonics.
Sign up below.