Erbium-doped photonic crystal fiber lasers optimization by microstructure control: experimental study analysis

Two home-made erbium-doped PCFs are used to experimentally study how the PCF microstructures affect the performance of tunable ring lasers made of these fibers. It is found that significant improvement of lasers performance can be obtained. In particular a laser power of 98 mW and slope efficiency of 24 % (to our knowledge the largest reported so far) and also a threshold of 4.5 mW are obtained with the optimal configuration. From the analysis of experimental results it is found that the influence of the microstructure takes place through three mechanisms: overlapping between modal distributions and erbium-doped area, splice losses and passive propagation losses which are mainly due to radiation originated by the finite size microstructure of air holes.