Nd3+-doped Fluoride Fiber Amplifier Module With 10 dB Gain and High Pump Efficiency

Recently, Nd3+-doped fluoride fiber has attracted much interest, because it has the potential for optical amplification around the 1.3 μm communication band[1]. In terms of the effect of ESA(excited state absorption) and the probability of radiative transition, fluoride fiber is preferable to silica fiber as a host glass[2], However, some problems must be solved for the development of a practical amplifier. First, gain has not been sufficiently large for a practical pump power to be obtained from diode lasers. Second, gain has been obtained in wavelengths longer than 1.31 μm.