High Power Narrow-line Fiber Laser Research And Engineering

Compared with traditional solid-state lasers,fiber lasers can be widely used in many fields such as optical fiber communication,medical treatment,laser radar,laser frequency doubling and beam coherence synthesis,which have the advantages of good beam quality,high conversion efficiency,compact structure and high stability.High power,narrow linewidth fiber laser is one of the main goals and hotspots in fiber laser research.Stimulated Brillouin scattering(SBS)is a very important nonlinear effect in fiber.For single-frequency fiber lasers,the low threshold of SBS effect limits the power boost of narrow linewidth fiber lasers and how to effectively suppress SBS effects Is to improve the narrow linewidth fiber laser power difficult.In this paper,Based on white noise as the RF signal source,a three stage master oscillator power amplifier(MOPA)all fiber laser system is designed and built by phase modulation technique.The relationship between the spectral width of the signal and the SBS threshold of the fiber amplifier system is analyzed and studied.By changing the amplitude of the white noise signal,the spectral width of the signal can be accurately controlled,and the narrow linewidth quasi continuous laser output with a central wavelength of 1030.93 nm,a line width of 0.9 GHz and an average power of 90 W is obtained,the corresponding X direction and Y direction of the beam quality factor were M2X=1.23,M2Y=1.24.The research work in this paper is expected to provide a reliable theoretical basis and experimental basis for the industrialization of higher power single-frequency narrow linewidth fiber lasers.