Single-transverse-mode Q-switched fiber laser yields 180-µJ pulse energies
University of Southampton (Southampton, England) researchers report what they believe is the highest energy yet produced from a single-transverse-mode Q-switched fiber laser. The grou¥previously showed that a large-mode-area, low-numerical-aperture, single-mode waveguide design significantly reduces the small-signal gain efficiency and increases the energy-storage capacity of a fiber. Using this approach with further increased mode areas led to pulse energies as high as 180 µJ at 1558 nm, with corresponding peak pulse power of 3.6 kW from a diode-pumped, large-mode, erbium-doped-fiber Q-switched laser.
Based on its results, the grou¥believes that pulse durations could be reduced to below 10 ns, with a resultant increase in peak power, by reducing the erbium concentration. Furthermore, average powers greater than 1 W and correspondingly higher pulse-repetition frequencies could be obtained by incorporating a large-mode-area inner core in a cladding-pumped fiber geometry.