Thulium doped fiber amplifier for the first window from 790 nm to 850 nm with 690 nm/1400 nm dual pumping

We demonstrate an optical amplifier with 30 dB gain for the 850 nm window using specialized fiber and practical pumping wavelengths of 690 nm and 1400 nm. The experimental results were achieved after thorough calculations, made by molecular dynamics simulation, provided guidance on physical parameters.