Upconversion channels in Er:ZBLALiP: a multicolour, microspherical light source for microphotonics

We present results on the realization of an all-taper-coupled, microspherical light source fabricated from the erbium-doped fluoride glass ZBLALiP. We observe whispering gallery mode lasing at 1.55 mum, in addition to upconversion processes which give rise to fluorescent emissions at multiple wavelengths from the ultraviolet to the infrared. A single-mode, tapered fibre coupling scheme -which serves to both launch pump light at 980 nm into the microresonator cavity and collect the resulting infrared lasing -is employed. We demonstrate the use of a second, separate fibre taper to outcouple the upconversion spectrum over several hundred nanometres. Thirteen discrete emissions ranging from 320 to 850 nm have been observed in the upconversion spectrum.