# Low-Cost DLW Setup for Fabrication of Photonics-Integrated Circuits

## TL;DR

This paper presents a low-cost system for making photonic circuits using laser writing, enabling affordable and accessible prototyping for research.

## Contribution

A low-cost Direct Laser Writing system for fabricating photonic-integrated circuits is introduced, reducing reliance on expensive infrastructure.

## Key findings

- The system achieves a resolution of 10 µm and successfully patterns structures like waveguides and diffraction grids.
- It uses SU-8 photoresist on ITO-covered glass substrates, with a custom user interface and slicer for operational flexibility.
- The approach is suitable for academic settings and enables rapid prototyping of photonic-integrated circuits.

## Abstract

The development of photonic-integrated circuits (PICs) for data communication, sensing, and quantum computing is hindered by the high complexity and cost of traditional fabrication methods, which rely on expensive equipment, limiting accessibility for research and prototyping. This study introduces a Direct Laser Writing (DLW) system designed as a low-cost alternative, utilizing an XY platform for precise substrate movement and an optical system comprising a collimator and lens to focus the laser beam. Operating on a single layer, the system employs SU-8 photoresist to fabricate polymer-based structures on substrates such as ITO-covered glass. Preparation involves thorough cleaning, spin coating with photoresist, and pre- and post-baking to ensure material stability. This approach reduces dependence on costly infrastructure, making it suitable for academic settings and enabling rapid prototyping. A user interface and custom slicer process standard .dxf files into executable commands, enhancing operational flexibility. Experimental results demonstrate a resolution of 10 µm, with successful patterning of structures, including diffraction grids, waveguides, and multimode interference devices. This system aims to transform PIC prototype fabrication into a cost-effective, accessible process.