Yb-Doped Pedestal Silica Fiber Through Vapor Phase Doping for Pulsed Laser Applications

This letter describes successful fabrication and detail characterization of ytterbium (Yb)-doped pedestal aluminosilicate fibers through vapor phase doping technique using modified chemical vapor deposition system (MCVD). Fabricated preforms have uniform step-index profiles devoid of any profile ripples, central dip, and/or core-clad interface defects, which are very common to the preforms made by a solution doping method. Fibers with a pedestal design exhibit good optical properties, low photodarkening-induced losses, high SNR values, and higher efficiencies making them suitable for high-power pulsed laser applications as compared with normal Yb-doped fibers. One of the pedestal fibers has demonstrated the output energy of 186 μJ with the 1.86-W average power. The pulse has a width of 100 ns at a 10-kHz repetition rate, which provides a peak power of 1.86 kW.