During the past 18 months or so, the subject of fibre lasers has been pretty much unavoidable. A walk down the aisles at any of the major exhibitions reveals yet more new launches from an ever-increasing number of manufacturers and suppliers adding fibre laser capabilities to their portfolio.
It comes as no great surprise, then, that fibre lasers are uppermost in the minds of industry experts when it comes to discussing growth areas within photonics.
Fibre lasers
‘There has been a lot of talk about fibre lasers,’ says Douglas Neilson, managing director at UK distributor Photonic Solutions, ‘but it’s only really in this past year that there has been any real volume deployment at the higher power levels in the automotive space. Higher numbers of low power units (10-20W) have been placed in the Far East, demonstrating growth and displacement of existing technology in the lower cost marking area. Overall, though, the low barriers to entry for manufacturers in creating a fibre laser product line has led to a lot of product options appearing on the market, but very few manufacturers are making money out of this space at the moment.’
Werner Wiechmann, product line manager for advanced lasers at JDSU, adds: ‘We are active in gas lasers, but as expected, this is a sector that is declining in volumes – but not as fast as we had predicted. From a broader perspective, the industry trend is going towards fibre lasers and these lasers will certainly enhance and expand the overall capabilities of photonics. An example of this is in remote laser welding, where fibre lasers are ideal because of their excellent beam quality. They are also expanding capabilities in precision micro-machining. The higher pulse repetition rates – albeit at lower pulse energy – also make fibre lasers particularly suited to scribing applications in markets such as solar cells and semiconductors.’
Mark Greenwood of GSI is another expert who has seen widespread acceptance and growth of the fibre laser market. ‘There has been a big push on fibre lasers across the industry,’ he says, ‘and nowhere is this more evident than in Trumpf’s acquisition of SPI, giving it a major fibre laser capability where it had little before. We’re finding that we’re starting to get a lot of requests from our customers in China for fibre lasers, because they are relatively cost effective. It’s not just price though; beam quality on fibre lasers is so good that they’re even making inroads into drilling markets. We have an aerospace customer using fibre lasers for just this purpose.
Concluding the discussion on fibre lasers, Chris Castle, marketing development manager at JDSU, says: ‘Aside from the technology aspect, reliability is a driving factor, as this lowers the cost of ownership. Fibre lasers certainly have a good track record for reliability, so this is another reason why the future looks good for them.’
Diode lasers
While fibre lasers continue to grab all the headlines, there have been developments in other areas too and, in particular, in the field of diode lasers.
‘Generally, there is a trend for large gas lasers to be replaced by DPSS lasers’, says Neilson of Photonic Solutions. ‘When it comes to replacing existing lasers, the customer has to evaluate both running costs of the existing and proposed new systems versus replacement capital costs. Sometimes, it’s easier to stick with what you have, particularly if it is working adequately – albeit at a higher running cost. However, for greenfield sites, it’s a much easier decision to opt for newer, more efficient, smaller footprint lasers, such as the DPSS option.
‘The higher power diode laser has real potential – and is already building on its excellent properties, such as longer life, greater efficiency and greater availability. There is still an amount of beam conditioning required, but it’s almost at the “plug and play” stage. Indeed, such advantages have implications for applications such as automotive production lines, as they will be able to fit more lasers into a smaller footprint and achieve more complex procedures at a comparatively lower cost.
‘Another future development likely will be the availability of more direct diode wavelengths, meaning there is no longer the need for costly and complex wavelength conversion techniques to select the required wavelength’
Franck Leibreich, manager of high power diode laser marketing at JDSU, says that the driving forces in the diode market are brightness and dollar per watt. ‘Diodes have many advantages, and with increases in power and brightness, we believe they will soon be replacing traditional lasers in many applications. The advantage of having many different wavelengths is that the range of applications is very broad. For example, in the cosmetic market, the availability and lower price of mass produced diodes has meant that laser-based skin treatment equipment has moved out of the hospital and salon market and into the home consumer market.
GSI’s Greenwood adds: ‘The direct diode market is still relatively small, largely due to poor beam quality. We have just instigated a research programme aimed at solving this problem, in fact.’
Other areas of growth
There are subtle shifts in markets and small steps forward in technology right across the photonics industry and, in each case, these open up new application areas. Arzu Ozkan, product line manager for bio instrumentation at JDSU, adds: ‘New laser performance options have enabled cost savings for the end customer. The cost decreases have increased the range of biomedical applications for lasers, which now include haematology, DNA sequencing, confocal microscopy, retinal imaging, drug discovery and many more.’
Technology advances are most certainly behind increases in speed, as more ultrafast lasers appear on the market. GSI’s Greenwood adds: ‘We see some movement in ultrafast lasers, which are emerging now into industrial markets. Everyone seems to have one at the moment, but their application has so far been restricted to the high-end scientific market.
‘We’re certainly seeing growth for nano and picoseconds lasers,’ says Mark Sobey, senior vice president at Coherent, ‘particularly for applications such as in micromachining addressing the micro-electronics market. The picosecond technology today requires fibre hybrid lasers, since fibre alone struggles beyond certain peak power levels. Increasingly, touchscreen mobile devices are patterned using nano and picoseconds lasers in this way.
Coherent has also established a niche for itself in high-power, optically-pumped semiconductor lasers. ‘The main advantage here is the compact size,’ says Sobey. ‘It’s not much bigger than a mobile phone – and has replaced argon ion lasers in anything from light shows to medical and forensic investigation.
‘CO2 lasers have also improved in terms of reduced footprint. They used to be large, expensive-to-operate, cumbersome and requiring complex utilities, but now they can be built into compact, sealed tools making them attractive to a lot of integrators.’
To conclude this insight into laser developments, it seems fitting to return to the topic of fibre lasers – and a warning that they may not provide the answers to everything. ‘Fibre lasers have their limitations,’ says Sobey, ‘since they struggle to cut many sheet metals thicker than 3mm, so there is still room for more high power CO2 /Nd:Yag/disk lasers in this area.
‘Our conclusion would be that the market is far from being “all fibre” any time soon. Just like many other laser sources it will do well in specific segments that align well with its properties and benefits. However, it still has many shortcomings that are overcome by other types of lasers, some of which may change with time, many of which will remain a barrier for fibre for the long term.’
