Brightness Scaling Based on 1.55 μm Fiber Amplifiers Coherent Combining

Abstract

Modulation multiplexing and beam cleanup are efficient techniques to coherently combine multiple fiber laser sources and achieve high power and very good beam quality. Using modulation multiplexing, three fiber amplifiers are coherently combined with a residual phase error of λ/30. Using beam cleanup by stimulated Brillouin scattering in a multimode gradient-index fiber within a ring cavity, coherent combining of two fiber amplifiers with 50% efficiency and 99% slope is achieved. Further potential of these techniques is also discussed.

Keywords:

• fiber optics amplifiers and oscillators
• laser beam combining
• phase modulation
• scattering
• stimulated Brillouin