Incoherent Multi-Wavelength Emission in the Wavelength Range 1500-2100 nm

In this paper, an innovative incoherent light source, based on the amplified spontaneous emission (ASE) phenomenon, is proposed. It is pumped at 980 nm and is based on a Tm:Er:Yb:Ho co-doped germanate glass fiber. The simulation predicts multi-wavelength emission peaks in a bandwidth of over 543 nm, in the wavelength range 1500-2100 nm. A numerical home-made solver, based on a nonlinear rate equations approach, has been ad hoc developed. The optimized ASE source is obtained by using a global optimization search based on a particle swarm optimization (PSO) algorithm, by varying the dopant concentrations, the fiber length and the input pump power. A total ASE output power as high as 50.71 mW is predicted for the optimized device.

I. Introduction

Amplified spontaneous emission (ASE) sources are wideband sources of incoherent light largely used in many different fields. These sources can work in the infrared wavelength range, which allows their usage in remote sensing, pollution environmental sensing, medicine, gyroscopes, and ghost imaging [1]-[7]. ASE sources can be obtained from many different kinds of rare-earth doped glass fibers, including silica, chalcogenide, germanate, antimony, tellurite, fluorozirconate and fluorophosphate glasses [8]-[11]. Germanate glasses show interesting properties, such as high dopant solubility and high physicochemical stability [9], that make them suitable for fibers co-doped with several different rare earths. However, modeling and optimization of glasses doped with many different rare-earth ions is not trivial, because of the need to know a high number of spectroscopic parameters and to consider many rare-earth ion transitions and energy transfer phenomena.