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Breakthrough delivery fiber to enable ultrafast high-power laser processing

The PULSE project has now packaged a unique fiber design into a rugged water-cooled laser-light cable ready to enable a new era in ultrafast light delivery for advanced manufacturing.

Industrial Technologies

Increased power scaling of ultrafast lasers can provide new possibilities for a range of industrial manufacturing. The large scale of kW class ultra-short pulse (USP) lasers mean efficient conveyance of the laser output to the workpiece will be critical for the adoption and exploitation of these new high-power laser sources. The use of fiber-optic beam delivery has been the key feature in the industrial application of high-power solid-state continuous-wave (CW) lasers; however, this approach cannot be directly translated for use with ultrafast lasers due to the exceptionally high peak powers which can easily reach up to Giga-Watt levels. The recent development of microstructured hollow-core fibers has made it possible to confine the laser light inside a small hollow core and transmit pico- and femtosecond pulses of high energy with excellent beam quality. However, the cost of these complex fiber structures means costs are high. This new delivery fiber is a result of collaboration between Ampliconyx, Finland and Ceram Optec, Latvia who combined their expertise in fiber design and ultrafast photonics to realise this innovation. Ultrafast lasers are being used in an increasing number of applications, as they provide unmatched precision and high-speed processing of materials. Initial test results indicate exceptionally low sensitivity to bending which is an essential characteristic of most beam delivery systems. This means the laser beam is transported efficiently and authentically from the high-power USP laser source to the target point on the workpiece. Detailed characterisation of the delivery fiber is now underway at the Mittweida University of Applied Sciences where a range of high-power lasers up to multi-kW level average power and mJ pulse energies will be used in the testing programme. For wavelengths around 1μm, attenuation values between 10 and 20dB/km or approximately 0.3% per meter are anticipated over the 900–1100nm spectral range. With correct beam launching, the delivered beam quality at the output of the laser-light cable is expected to be very high with an M2 around 1.3 and highly symmetric far-field profiles. This new fiber is expected to alleviate challenges associated with free-space beam delivery of ultrafast lasers for material processing such as alignment sensitivity of mirror-based systems, beam path contamination issues with dust and particles and the need for high stability highly engineered structures.