11 mJ all-fiber-based activelyQ-switched fiber master oscillator power amplifier

Abstract

We report a high energy all fiber format nanosecond pulsed laser source at ∼1064 nm in master oscillator power amplifier (MOPA) configuration. The seed source is an acousto-optic Q-switched fiber laser with a varied pulse duration and repetition rate. The output average power of the oscillator is ∼30 mW and two pre-amplifiers were developed to boost the average power to ∼3 W. Pulse energy of >11 mJ for ∼660 ns pulses at 3 kHz was achieved in the final power amplifier using a commercial 50/400 μm (core/cladding diameter) double cladding Yb-doped fiber (DCYF).

Modeling of a Q-switched master oscillator power amplifier fiber laser and gain saturation properties

“…The self-pulsing of a high power Yb-doped fiber amplifier in the MOPA configuration has also been reported [15]. Moreover, a high energy QSW Yb-doped fiber laser at ∼1064 nm in an MOPA array has been empirically examined [16]. Note that the saturation power in an MOPA is relatively low compared to the typical output powers, even with a large mode area DC fiber.…”

“…The model has been derived directly from the standard rate equations [18][19][20]51]. In the limiting cases, equation ( 15) is simplified to: P out = P in exp (γ 0 L) for P in ≪ P out (16) P out = P in + (γ 0 L) P sat for P in ≫ P out (17) which indicate that for low input energies, the overall gain (G = P out /P in ) is exponentially proportional to the gain-length product, the gain coefficient becomes equal to γ 0 according to equation ( 16), and for the high input signals, the gain reduces to the saturated value given by equation ( 17) [18][19][20]51].…”

Efficient extraction of high pulse energy from partly quenched highly Er3+-doped fiber amplifiers

“…In the absence of quenching, high-energy pulse amplification in rare-earth-doped fiber amplifiers, including EDFAs, is well understood [1][2][3][4][5][6][7][8][9][10][11]17,[45][46][47][48]. In the unquenched case, amplified spontaneous emission (ASE) or spurious lasing limits the energy that can be extracted (E extractable ) in a high-energy signal pulse to a few times the intrinsic saturation energy E IS , or say, at most 10 times [46][47][48] if the stored energy and the extraction efficiency are both at their practical limits. Specifically, the extractable energy is related to the gain according to [47] E extractable = E IS G initial Np ,…”

Er-Doped Pulsed Fiber Source Based on the Electrooptical Modulator

“…При пассивном методе применяются насыщающиеся поглотители, пропускающие излучение при достиже-нии определенной мощности в резонаторе. В волоконных лазерах в ка-честве насыщающихся поглотителей могут использоваться оптические волокна, легированные ионами с полосой поглощения в спектральной области излучения лазера [1], углеродные нанотрубки [2], графен [3], полупроводниковые насыщающиеся поглотители SESAM [4]. К пас-сивной также относится модуляция добротности за счет ион-ионного взаимодействия в волокнах с высокой концентрацией активной приме-си [5,6].…”