High Performance Laser Amplifiers at 1.5 µm using E-Gum Evaporated Hafnium Di-Oxide Coatings

E-gun evaporated Hafnium di-Oxide anti-reflective coatings are shown to be an attractive alternative for sputtered Silicon Oxide AR coatings. Laser amplifiers were fabricated using this material and a modal reflectivity as low as 1.7×10-4 was obtained. A single pass gain of 26 dB together with a ripple as low as 2 dB for the TE mode were measured. Furthermore a 3 dB output saturation power of +8 dBm and a fiber coupling loss of 3.5 dB/facet were measured.