Characterization of single-crystal sapphire fibers for optical power delivery systems

Sapphire single-crystal fibers with diameters of 110 μm and lengths of over 2 m have been grown by the laser-heated pedestal growth method. The fibers are free of imperfections such as voids and bubbles. The minimum loss of 0.5 dB/m was measured in the near infrared at 1064 nm. Absorption loss at 2936 nm was 0.88 dB/m with a damage threshold higher than 1.2 kJ/cm2 for 110-μs-long pulses making tissue ablation feasible with fibers several meters in length.