Robust 1.69 μm Random Fiber Laser With High Spectral Purity Based on Ordinary Fibers

Laser emissions at 1.6–1.7 μm band have captured considerable attention in recent years. However, limited by the available emission spectrum of typical rare-earth-ion doped gain fibers, it is extremely difficult to realize highly stable laser output in this wavelength region with a simultaneous high spectral purity and high output power. To address these problems, a cost-effective robust random fiber lasing scheme is proposed to generate the high-power and high-spectral-purity laser output at 1.69 μm. The maximum output power is 7.55 W and the spectral contrast between the output lasing and the pump is as high as 24.3 dB. Both the short-time temporal characteristics and the long-time output power fluctuations are measured, which shows excellent stability and robustness of the laser configuration. This work provides an alternative approach to realize high-performance 1.6–1.7 μm band lasing output which is of particular significance for potential applications.