Fabrication of optical microstructures using direct laser writing and deep reactive ion etching technologies

This paper presents the design, fabrication and optimisation of polymer-based optical waveguides using Direct Laser Writing (DLW) and Deep Reactive Ion Etching (DRIE) technologies. The study focuses on the design of single-mode waveguides for operation in the O- and C-bands (1310nm and 1550nm, respectively), using OrmoClear®FX as the core material and Lumogen OVD Varnish for cladding. Optical loss measurements of the OrmoClear®FX core material demonstrated low propagation losses, with values of 0.54dB/cm at 650nm and 0.60dB/cm at 1310nm for planar waveguides. In contrast, the measured losses were higher at 1550nm, reaching 1.20dB/cm. The designed waveguides were fabricated using a three-step process: (1) the creation of a silicon master template via DLW and DRIE, (2) stamp casting using Polydimethylsiloxane (PDMS), and (3) fabrication of the waveguides using polymer deposition and UV curing. The fabricated waveguides achieved widths of 1.7μm and depths of 1.4μm, achieving the desired waveguide dimensions for single-mode operation.