Ytterbium-doped fiber laser pumping of a thulium-doped ZBLAN blue fiber laser

The thulium-doped ZBLAN fiber laser converts infrared radiation in the range 1100-1160 nm to visible radiation around 480 run through an upconversion pumping process. A brief description of the laser through a rate equation analysis modeling is presented. A compact experimental setup using a diode-pumped Yb3+ fiber laser at 1108 nm is presented. Single transverse mode blue emission at 482 nm with a maximal output power of 96 mW was obtained. A slight increase of the laser threshold due to photoinduced losses from 103 mW to 240 mW was observed, which is significantly less than previously reported values. Further optimization of the laser efficiency is proposed using Raman fiber laser pumping at 1125 and 1160 nm. Numerical simulations are used to calculate the expected increase in blue output power.