Jörg Schwartz, email@example.com
SOUTHAMPTON, UK − Fibre lasers, many experts agree, have potential well beyond their current uses, including high-power applications. The established benefits of fibre lasers – such as high wall plug efficiency, good beam quality and brightness, high reliability and simple operation – are also what the high-power guys want.
This view is backed up by what’s going on in the industry. Southampton, UK-based SPI Lasers, now part of industrial laser giant Trumpf, is introducing a variety of high-power OEM fibre lasers in the 300- to 500-W range that can be incorporated into laser systems for industrial cutting and welding applications or can be used as stand-alone units.
In Germany, IPG Laser GmbH has announced that it is supplying car maker BMW with multikilowatt, continuous-wave ytterbium fibre laser systems for a new production line where automotive doors are welded. And Florida-based Laser Photonics, which makes laser systems for materials processing, has announced that its High-Power Fiber Laser Cutting Systems Div. is expecting at least 300 per cent growth in sales in 2009.
Fibre-coupled diode lasers cover a range of applications, but fibre laser pumps show all signs of being the next big thing. Photo courtesy of Dilas.
The future is literally bright for high-power fibre lasers, driving the demand for better – and cheaper – pump sources, or diode lasers. Over the past two decades, diode-pumped solid-state lasers, workhorses in the industrial laser field, have created one of the primary markets for diode lasers.
Incorporating fibre lasers into high-power applications can be challenging. A lot of light must be pushed into relatively small core fibres. This can be achieved either with multiport/multistage couplers and several low- to medium-power lasers or with fewer pumps and higher power. The former comes with higher assembly and integration costs, and the latter has to overcome challenges in squeezing the output of diode bars or stacks into the fibre without losing too much power.
Most major diode laser makers are addressing the fibre laser opportunity by expanding their portfolio and tackling the challenges. In recent news, Jenoptik presented new air-cooled fibre-coupled diode lasers intended for fibre laser pumping, whereas diode laser specialist Dilas released a wavelength-stabilized pump laser for pumping narrow absorption-active materials as found in fibre lasers. But aside from all technical progress, a key challenge is keeping the cost down, as Thomas Brand, head of R&D Optics at Dilas, explains. On the other hand, he sees that diode laser makers are under pressure to play in this market: “Anyone [diode laser manufacturer] missing this development will not be around in five years’ time.”
So diode lasers continue to maintain their importance as laser pumps, but the question is to what degree fibre lasers will take the place of solid-state lasers. The fact that the outlook of fibre laser pumps is uncertain is well-illustrated by an interesting unit released by Denmark-based Crystal Fibre A/S. Its aeroLase-350 is an almost complete fibre laser for up to 350-W output (which can take between one high-power pump and 61 lower-power sources) with just one “minor detail” not included: the pump diodes.