100 hrs endurance test of a DUV laser beam delivery via a hollow-core photonic crystal fiber patchcord

We report on the development of inhibited-coupling hollow-core photonic crystal fiber with record-low transmission loss of ⪅50 dB/km at 266 nm, and solarization-free. 2 meter-long patchcords with SMA terminations were made and their UV handling and lifespan were tested. A laser beam from a 266 nm wavelength laser-source emitting 1 ns wide and 30 μJ energy pulses was injected into the hollow-core fiber patchcord, achieving a total transmission rate of 93%. The laser beam was kept continuously coupled to the patchcord for over 100 hrs. The results show excellent stability in transmitted power (fluctuations of less than 2.6%) and in mode quality. To our knowledge this the first fiber guidance of DUV laser that combines high energy handling and long lifespan. The results mark a major milestone in the adoption of fiber UV laser beam delivery by the industrial community.