Thulium-doped fiber amplifier for blue light signal amplification

Fluoride-based thulium-doped visible light fiber amplifier (TmVLFA), which can be used to amplify the blue light signal for a visible light communication (VLC) system, is theoretically demonstrated for the first time according to the best of our knowledge. The transition rate equations and power propagation equations are solved to predict the dependence of the gain and noise figure on fiber parameters. The numerical results show that with the pump wavelength 1150nm and pump power 800mW, 2.75m long thulium-doped fiber can amplify blue light (480nm) signal up to 33.3dB, and the noise figure is in the range from 3.0 to 3.5 dB. The model and numerical results encourage the use of fiber amplifier in VLC system for blue light amplification to extend the range of VLC.