High energy, monolithic fiber femtosecond lasers

High efficiency, monolithic fiber chirped pulse amplification system for high energy femtosecond pulse generation

“…With a relatively small A eff of only 310 µm 2 , we have demonstrated an Er-doped HEM fiber amplifier producing >100 µJ pulse energy in the femtosecond regime output from a linear propagation CPA fiber-optic architecture. This matches the pulse energy output capability of state-of-the-art fiber-optic CPA systems with amplifiers leveraging 4 × larger A eff and adaptive pulse shaping to compensate for SPM-induced pulse distortion [13]. Based on this demonstration, we expect that much higher pulse energy scaling is possible in monolithic fiber-optic CPA systems using this HEM amplifier concept.…”

“…Historically, a ceiling on erbium doping concentration at about 4.0 × 10 25 ions/m 3 in silica glass LMA fibers has been imposed by strong ion clustering effects, where the close spatial proximity of erbium ions leads to cooperative energy coupling into transitions that are parasitic to the laser transition efficiency [13,14,41]. Owing to these ion-ion interactions at high erbium concentration, the upper laser level ( 4 I 13/2 ) lifetime decreases when pump power is increased, further degrading amplifier efficiency [42,43].…”

“…The continuing symbiotic advancement of optical fibers (where a smaller doped core is surrounded by a larger mode-confining cladding) and highly efficient pump sources, such as high brightness, fiber coupled laser diodes [6] and high power Raman fiber lasers [7], continues to trigger both research and commercialization of high power fiber lasers [8][9][10][11][12]. Meanwhile, monolithic fiber-optic femtosecond fiber laser systems now offer pulse energy up to 100 microjoules (µJ) using the CPA scheme with large mode area (LMA) erbium-doped (Er-doped) fiber amplifiers with A eff up to 1060 µm 2 [13,14].…”