Protective windows are essentially the only optic consumables in fiber laser systems. This optics are also known as cover glass, debris window and cover slide and are available in various shapes and sizes.
Focusing lenses in fiber laser cutting head are very sensitive to any type of contamination. This is one of the main reasons for poor laser performance and potential downtime of laser operations.
No laser system is perfect and some debris, fume or backspatter can occasionally reach the lens. This situation occurs for many high power laser systems, including fiber lasers.
For this reason, fiber laser manufacturers install protective windows to protect the focusing lens from contamination. The protective window is positioned below the focusing lens and is a barrier between the lens and the sheet.