Příprava optických polymerních mikrostruktur s využitím technologií přímého laserového zápisu a hlubokého reaktivního leptání

Abstract

This thesis focuses on the design, fabrication, and optimization of single-mode optical waveguides utilizing direct laser writing (DLW) and deep reactive ion etching (DRIE) technologies. Building upon foundational work from the bachelors thesis, this work integrates theoretical photonic principles, coupling mechanisms, and material characteri-sation to address encountered challenges. The work begins with a theoretical background on the principles of optical waveguiding, and continues with the theoretical design of single-mode optical waveguides for operation in the O- and S-bands (1308.2 nm and 1549.1 nm), using materials OrmoClear®FX for the core and Lumogen OVD Varnish 311 BASF as the cladding. The fabrication process is divided into three stages: the creation of a silicon master template with the help of photoresists MICROPOSITS1818G2 and S1805G2, then PDMS stamp moulding from the master template and finally, optical waveguide fabrication. Comprehensive characterization is conducted to evaluate waveguide performance. Measurement techniques, including refractive index analysis and optical loss evaluations, are used. The results reveal significant advancements in waveguide dimension accuracy and process reliability, achieving structures with dimensions as small as 1.7 μm width by 1.4 μm depth. Planar (2D) waveguides demonstrated losses as low as 0.54 dB/cm at 650 nm and 0.60 dB/cm at 1310 nm, with losses increasing to 1.20 dB/cm at 1550 nm. 3D channel waveguides encountered higher losses due to irregular facet preparation, precluding reliable loss measurement.

This thesis focuses on the design, fabrication, and optimization of single-mode optical waveguides utilizing direct laser writing (DLW) and deep reactive ion etching (DRIE) technologies. Building upon foundational work from the bachelors thesis, this work integrates theoretical photonic principles, coupling mechanisms, and material characterisation to address encountered challenges. The work begins with a theoretical background on the principles of optical waveguiding, and continues with the theoretical design of single-mode optical waveguides for operation in the O- and S-bands (1308.2 nm and 1549.1 nm), using materials OrmoClear®FX for the core and Lumogen OVD Varnish 311 BASF as the cladding. The fabrication process is divided into three stages: the creation of a silicon master template with the help of photoresists MICROPOSITS1818G2 and S1805G2, then PDMS stamp moulding from the master template and finally, optical waveguide fabrication. Comprehensive characterization is conducted to evaluate waveguide performance. Measurement techniques, including refractive index analysis and optical loss evaluations, are used. The results reveal significant advancements in waveguide dimension accuracy and process reliability, achieving structures with dimensions as small as 1.7 μm width by 1.4 μm depth. Planar (2D) waveguides demonstrated losses as low as 0.54 dB/cm at 650 nm and 0.60 dB/cm at 1310 nm, with losses increasing to 1.20 dB/cm at 1550 nm. 3D channel waveguides encountered higher losses due to irregular facet preparation, precluding reliable loss measurement.