High-energy single-frequency pulsed fiber MOPA at 1064 nm based on a hybrid active-fiber

Abstract

We report a single-frequency pulsed Yb-doped fiber master-oscillator-power-amplifier at 1064 nm producing output with pulse energy of 0.6 mJ for a pulse width of 95 ns at a pulse repetition frequency of 5 kHz. Integral to this laser design was the application of a hybrid active-fiber, which integrated a length of heavily Yb-doped phosphosilicate fiber (with a core diameter of 50 μm) with a silica gain fiber (with core diameter of 35 μm). This was used in the power amplifier stage to both suppress stimulated Brillouin scattering and to enhance the gain saturation for improved efficiency and spectral signal to noise ratio. The seed pulses were pre-shaped so that sawtooth-like pulses were obtained after amplification, this having the effect of preventing linewidth broadening induced by self-phase modulation. A spectral linewidth of ∼15 MHz was measured at the maximum peak power of 6.3 kW.

Recent progress of high-power single-frequency all-fiber oscillators and amplifiers

“…Besides, the pulse laser was preamplified by silica fiber, which enhanced the gain saturation of highly-doped phosphosilicate fiber. The seed pulses were pre-shaped so that sawtooth-like pulses were obtained after amplification to prevent linewidth broadening induced by SPM [36].…”

Stokes linewidth narrowing by stimulated Brillouin scattering in liquid media

“…[15][16][17][18][19][20] In addition, this study demonstrates that the SBS has a controllable output linewidth. [21][22][23][24][25] Spectral density S ( ) w of the Stokes radiation is given by: 26) S n ncA…”

Pulse shaping, high average power narrow linewidth Er, Yb co-doped fiber amplifier

“…And different pulse shapes have different compensation effects. In addition, the pulse pre-shape method can also suppress the linewidth of the singlefrequency pulsed lasers [23,24].…”