Characterization and stabilising dynamic phase fluctuations in large mode area fibres

摘要: Fibre amplifiers exhibit rapid time dependent phase fluctuations due to the environment and thermal other effects associated with pumping lasing processes. We characterise these effects in a large mode area fibre amplifier having an output power of 260W limited only by pump power. The amplifier retains its coherence even at highest available negligible linewidth broadening. Phase are characterised low-amplitude power-independent jitter superimposed on power-dependent drift heating. also measure phase fluctuations COTS preamplifier find they predominantly amplitude periodic oscillations at 110Hz, probably induced fluctuations. two were combined series give high gain amplifier chain actively stabilised precision (~l/37 rms) using piezo-ceramic stretcher incorporated into PC-based feedback loop.