The heart of the Inkcups Cobalt laser engraving system is a Q-switched Fiber laser. The laser used has attained the position of market leader in the incredibly demanding Asian market, and is making major progress in penetrating the European and US markets. To date, there are over 2,000 of these Fiber laser units installed worldwide. These single mode lasers are so appealing because of their perfect beam characteristics, air cooled operation, high efficiency, and compact size; all significant benefits over other laser systems.
An advantage these single-mode fiber lasers have over current lasers is their use of highly reliable single emitter diodes with projected lifetimes greater than 100,000 hours of continuous or pulsed operation. They also have the ability to focus the beam to very small spot sizes with long focal length lenses. They have a compact size, maintenance-free operation, and consistent beam properties independent of power level or pulse duration. Because the fiber laser is a direct substitute for current YAG systems, it can offer better beam quality, as well as the same, or in most cases, improved performance with the added benefits of the high wall plug efficiency. Another convenient feature is that NO DIODE BAR REPLACEMENT IS NECESSARY
1. Fiber lasers are publicized as having the capability to displace other lasers currently used in industrial applications. How will this technology impact the marketplace?
“Fiber lasers hold great promise for a wide range of applications because they are truly solid-state with a minimum of exposed optical interfaces, have very high efficiency, and are capable of exceptional beam quality. In the near future, the most important markets they will address are micromachining, automotive, and biomedical.
The high beam quality and 1 μm wavelength mean they can directly replace Nd: YAG lasers in many industrial applications, both diode and lamp pumped. The already low cost and high reliability of CO2 lasers may limit the growth as CO2 laser replacements, but high beam quality and the ability to both cut and weld with the same fiber laser could pose a challenge to CO2 down the road.
Technologically, one of several challenges in building a fiber laser is how to effectively couple the pump light into the gain fiber. Single emitters address one class of coupling approach and fiber-coupled bars address another class. The choice of bar or single-emitter pump depends on the power level and ultimate performance characteristic of the fiber laser. Broadly speaking, low-power fiber lasers and some pulsed fiber laser architectures will likely use single emitters; high power (>100 W) fiber lasers will likely use fiber-coupled bars. However, there already exist fiber laser architectures in the marketplace that break both of those guidelines.“
— Robert S. Williamson III, Ph.D., Director of Business Development, Alfalight, Inc.
“Fiber lasers will completely replace CW Nd: YAG lasers for new installations in 2 to 3 years. CO2 lasers will compete with fiber lasers much longer due to their simplicity, very good beam property, and low cost. But, in metal cutting, for example, fiber lasers have a great chance to completely win in 3- to 5-year time.”
— Dr. Denis Gapontsev, Director & Vice President of R&D, IPG Photonics
“Both single-emitter laser diodes and laser-diode bars may be winners, depending on the application of the fiber laser. Today, bar pumping is more cost-effective for total power, whereas single emitter pumping provides greater lifetimes (especially when power cycled) and simpler thermal management. The usage pattern will depend on the power requirements, lifetime requirements, and the nature of the output (true CW or power-cycled). Most fiber laser manufacturers today use single emitters because of their proven reliability, but bar diodes seem to be making headway at the higher power levels. Still, as long as they remain close in price per watt, single emitters should continue to dominate.
I also expect to see single-emitter ensembles utilized in non-fiber laser products in the coming years. While fiber lasers pioneered the introduction of single emitters as laser pump sources, they make a lot of sense for end-pumping DPSS YAG lasers (including disk lasers) and can be used in direct diode material processing applications.”
— Andrew Leuzinger, Product Marketing – Laser, Optics, & Display Products, JDS Uniphase Corp.
“Initially, fiber lasers are targeting the higher-end systems, and more directly the YAG systems, but they certainly have the potential to move into any of the materials processing markets. It is going to take much higher reliability and lower cost to get there.
The cost of conventional, sealed CO2 lasers is coming down due to better technology and larger production volumes. There is still a lot of life left in the CO2 laser, particularly if issues with flexible beam delivery systems can be solved. That would be a tremendous step forward.
In the history of the laser business, there has always been new technology that carves out very nice niches, but the old technology is still there. Our biggest seller is still the laser we developed 20 years ago because it fits the market very well. Fiber lasers will also find areas that they fit well, but I am doubtful that they can totally obliterate the competition. In the next 3 to 5 years they will make a lot of ground, but we will be making just as much forward progress.”
— David Clarke, President, Synrad, Inc
2. The potential of fiber lasers is often linked to the progress of their pump source, diode lasers. What are your goals and expectations for diode laser technology?
“A general trend right now is to improve the efficiency of diodes, which will help people design new systems at lower costs and, at times, use fewer diodes. At the same time, it will help enable new markets. We are also working hard to improve diode reliability. Going from a lifetime of 10,000 hours now to 20,000 or 30,000 hours would reduce the cost of ownership for our customers.
We are doing this by improving all the steps in the process of building diodes. We are currently designing a much more efficient epitaxy and process for the wafer processing, as well as the assembly of the diode on the heat sink. When you add all of those details together you can obtain very high-efficiency, high-quality products.”
— Franck Leibreich, Director of Marketing – Diode Lasers, Spectra-Physics Division of Newport Corp.
Each of these lasers shares a universal ingredient – fusion spliced diode excited monolithic fiber lasers. The kilowatt units are manufactured by combining multiples of the highly reliable and wall plug efficient, (>25% wall plug), single mode lasers, and launching them via a small diameter step-index fiber. For example, a 10-kilowatt system can be delivered with a 300-micron diameter fiber and a beam property mm median < 12, as well as a wall plug efficiency of > 25%.
Models are available with average power levels up to 200 watts and near single-mode quality. Pulse durations are in the nanosecond domain, producing the high peak power required for high-quality marking.
Excerpts are taken from PTB Magazine.
May 05, 2005