Ultrafast laser inscription of a high-gain Er-doped bismuthate glass waveguide amplifier

An Er-doped bismuthate glass waveguide amplifier has been fabricated using ultrafast laser inscription. Under zero pump conditions, the 87.0 mm long waveguide exhibited a fiber-to-fiber insertion loss of 4.0 dB at 1618 nm, outside the Er³⁺ ion absorption band. We attribute =1.8 dB of the insertion loss to coupling losses, 0.2 dB to Fresnel reflections and =2.0 dB to propagation losses. When pumped using 1050 mW of 980 nm light, the amplifier exhibited a peak internal gain per unit length of 2.3 dB .cm^-1 at 1533 nm and a peak fiber-to-fiber net gain of 16.0 dB at 1533 nm. In this paper we also report the results of output power saturation and noise figure measurements. © 2010 Optical Society of America.