Although the power available from fiber lasers continues to increase year on year, and is a major contributor to increase cutting speed and quality, there continues to be an industry wide need to enhance cutting performance through controlling the intensity profile of the beam on/at the workpiece. Axicon based beam shapers have traditionally been used to create ring shaped beam profiles on the workpiece, and these ring profiles been shown to improve cutting performance. Most fiber laser cutting machine manufacturers now have some means of providing generating ring profiles that can undergo dynamic changes to shape. However both the axicon and the dynamic fiber laser beam shaping systems suffer from a small depth of focus to the rings they produce, making it difficult to maintain a constant (or at best, slowly varying) optical profile when cutting thick metal (> 15mm) The Light Tunnel Generator (LTG) was developed by PowerPhotonic to overcome the problem of small depth of focus. In this paper, we will describe the optical design of the LTG, and how it is able to create a ring shaped profile that only changes slowly through the depth of thick cuts. Results from real-world trials using LTG’s in the cutting of thick section metal will be provided. We will indicate which cutting regimes show benefits from adopting the LTG. The optical design and manufacturing techniques that underpin the Light Tunnel Generator are applicable to other laser applications where traditional beam shaping only works over a limited depth of field. Thus laser welding and laser cleaning (among others) have the potential to benefit from this approach too.