2025/08/09 by Hossein Fathi, Fathi, Hossein, Uttam Kumar Samanta +13 · 1 citation
Engineering · #Photonic Crystal and Fiber Optics #Optical Network Technologies #Advanced Fiber Optic Sensors
paper · pdf · doi:10.48550/arxiv.2508.06989
High-energy, narrow-linewidth nanosecond pulses are highly demanding for many applications that require high temporal and spatial coherence. However, the amplification of narrow-linewidth pulses is primarily limited by stimulated Brillouin scattering, which causes pulse instabilities, back-reflected pulses, and catastrophic damage effects on optical components. In this work, we present a 1.6 mJ narrow-linewidth nanosecond pulsed fiber laser system based on all-glass spun tapered double-clad fibers without employing any mitigating technique for the stimulated Brillouin scattering effect. The system delivers pulses with an 8 ns duration at a 100 kHz repetition rate, over 97.5% degree of polarization, a beam quality factor of M2 = 1.3, a spectral linewidth of 53.8 MHz, a 160 W average power, and 188 kW peak power with a slope efficiency of 97.6%. The degree of spatial coherence of the amplified signal was measured to be 0.94. Our results are highly valued in applications requiring high-energy, high-coherence pulses with spectral, spatial, and polarization characteristics in a compact system.