A Compact, high-power, fiber-based laser systems at 257.5nm and 1030nm for photocathode injector application in the Linac Coherent Light Source-II

With this potential application as photocathode injector in the Linac Coherent Light Source-II (LCLS-II), AdValue Photonics proposes to develop a compact, high-power, picosecond Yb-doped fiber-based laser at 1030nm and its 4th-harmonic generation at 257.5nm based on our well-commercialized fiber-based high-power picosecond green laser technology (50W average power at 515nm for glass cutting industrial application). An all-fiber mode-locked Yb-doped fiber laser, which was developed during the period of the year 2013~2016 under the support from another DoE SBIR program (entitled “100W Mode-locked Green Laser for GaAs Photoemission Guns”), delivers sub-picosecond laser pulses at 1030nm from a compact robust mechanical package. With a very short piece of chirped fiber Bragg grating and an AOM-based pulse picker, flat-top laser pulses with a pulse duration of ~20ps at a repetition frequency ~5 MHz near 1030nm will be generated as the seed laser. These well-tailored seed laser pulses will then be amplified up to mega-watt peak power by using our patented technology – a high-power, high-efficient Yb-doped fiber amplifier chain in an all-fiber monolithic compact platform. In the Phase I program, we promise to demonstrate >20W output power of 20ps laser pulses at 257.5nm at ~5MHz rep rate. The Phase II program will build a prototyping unit demonstrating such a compact UV laser at 257.5nm with 25W average power, 20ps pulse duration at ~5MHz rep rates and a 100W infrared laser at 1030nm as well, for its potential use in the photocathode injector in the Linac Coherent Light Source-II. In addition to its potential application in high-power synchrotron light sources, our proposed high-power, fiber-based, picosecond lasers from a UV wavelength to green and infrared wavelengths are also very useful for industrial material processing applications, for example high-precision laser cutting and drilling. One rapidly growing segment of the materials processing market is micro materials processing where ultrafast lasers. Ultrafast lasers provide a superior advantage when compared to CW, QCW or other pulsed lasers in certain applications where drilling, cutting and structuring quality and precision is critical, especially when working with sensitive materials and non-metals. Industrial needs for micro material processing application by using ultrafast lasers include aeronautics, electronics, medical and scientific industry segments. This market is dominated today by solid state lasers, however, fiber-based hybrid lasers utilizing specialty fibers in the master oscillator or amplifications stages are gaining traction. Market shift towards cloud computing, 5G technology, and OLED based flat panel displays to name a few, are driving the need for cost effective, scalable and ruggedized ultrafast fiber laser solutions to address the growing requirements of processing new and advanced materials in high volume.