Design of a mid-IR optical fiber amplifier based on a Pr3+:InF3 glass

Abstract

An optical fiber amplifier based on a fluoroindate fiber doped with praseodymium (Pr 3+ :InF3) has been designed. The chosen fiber has a double-cladding and a 2-D shape. The electromagnetic behavior of the fiber has been simulated via a Finite Element Method (FEM) software, and the design of the fiber amplifier has been performed via a computer code, solving the rate-equations and power propagation equations. The gain 𝐺 and the Amplified Spontaneous Emission (ASE) noise have been investigated as a function of different input parameters as the input signal power 𝑃 𝑠0 , the fiber length 𝐿 𝑓𝑖𝑏𝑒𝑟 , and the signal wavelength 𝜆 𝑠 . The simulated fiber amplifier exhibits a bandwidth 𝐵 𝐺 close to 𝐵 𝐺 = 100 𝑛𝑚 around the central signal wavelength  𝑠 = 4 µ𝑚, and a gain 𝐺 close to 𝐺 = 30.7 𝑑𝐵, when an input signal power 𝑃 𝑠 = 10 µ𝑊 and a pump power 𝑃 𝑝 = 75 𝑚𝑊 are considered. This pump value seems particularly low and further investigation will be performed to better understand this unexpected promising value.