UV laser micromachining of photonics materials

Greuters, Jako

Abstract

UV laser micromachining processes have been developed for materials typically used in photonics devices, i.e. indium phosphide, silicon, lithium niobate and fused silica, with the aim to provide alternative solutions for the currently established micromachining technologies o f chemical etching and diamond enhanced blade dicing.
The novel micromachining processes were developed with direct writing and mask projection systems. The direct writing system consisted of a 3rd harmonic Nd-YAG solid-state laser while KrF and ArF excimer lasers and a F2laser, were integrated into mask projection laser micromachining systems.
The material removal behaviour of all four materials was investigated by determining the average etch rate per laser pulse versus incident fluences. Comparison between the calculated and the experimentally determined threshold fluence for ablation was made and an Arrhenius type thermal model was tested against the material removal behaviour.
Both x and z-cut lithium niobate was used for UV laser micromachining processing and no difference between average etch rate or the final machined microstructures could be seen. With newly developed processes for cutting and passive fibre alignment v-groove machining, a passive fibre alignment platform was produced in x-cut orientated lithium niobate.
Complex 2-D structured microbenches were isolated from silicon wafers with the use of a newly developed laser cutting process based on the direct writing system. By combining this process with that developed for machining v-grooves, self-aligning microbenches with passive fibre alignment v-grooves were fabricated.
Planar and fibre based fused silica materials were machined with a fluorine laser micromachining system. In the planar substrates, ridge optical waveguides and micro­ mirrors were machined and the shaping and side polishing of optical fibres tips was attempted. Within photosensitive optical fibre, long period gratings were inscribed by use of mask projection technology. After process development, a combined gain flattening filter was produced.
These studies show that laser micromachining can fulfil a useful role in photonics device manufacture.

Citation

Greuters, J. UV laser micromachining of photonics materials. (Thesis). University of Hull. https://hull-repository.worktribe.com/output/4223219

• Thesis Type: Thesis
• Deposit Date: Jul 7, 2021
• Publicly Available Date: Feb 23, 2023
• Keywords: Physics
• Public URL: https://hull-repository.worktribe.com/output/4223219
• Additional Information: Department of Physics, The University of Hull
• Award Date: Nov 1, 2005