Design of Radiation-Hardened Rare-Earth Doped Amplifiers Through a Coupled Experiment/Simulation Approach

Abstract

Abstract-We present an approach coupling a limited experimental number of tests with numerical simulations regarding the design of radiation-hardened (RH) rare earth (RE)-doped fiber amplifiers. Radiation tests are done on RE-doped fiber samples in order to measure and assess the values of the principal input parameters requested by the simulation tool based on particle swarm optimization (PSO) approach. The proposed simulation procedure is validated by comparing the calculation results with the measured degradations of two amplifiers made with standard and RH RE-doped optical fibers, respectively. After validation, the numerical code is used to theoretically investigate the influence of some amplifier design parameters on its sensitivity to radiations. Simulations show that the RE-doped fiber length used in the amplifier needs to be adjusted to optimize the amplifier performance over the whole space mission profile rather than to obtain the maximal amplification efficiency before its integration in the harsh environment. By combining this coupled approach with the newly-developed RH RE-doped fibers, fiber-based amplifiers nearly insensitive to space environment may be designed in the future.

Design of fiber coupled Er3+:chalcogenide microsphere amplifier via particle swarm optimization algorithm

“…As an example, particle swarm optimization (PSO) approaches have been developed for the optimization and characterization of rare-earth-doped photonic crystal fiber amplifiers. [23][24][25] In this paper, an amplifying system operating close to 2.7 μm and based on Er 3þ -doped chalcogenide microsphere coupled to a tapered fiber has been optimized via a PSO approach. An accurate three-dimensional mathematical model for Er 3þ -doped chalcogenide microspheres 26,27 is employed for calculating the fitness function of the PSO procedure.…”

“…An accurate three-dimensional mathematical model for Er 3þ -doped chalcogenide microspheres 26,27 is employed for calculating the fitness function of the PSO procedure. [23][24][25] The core of the developed numerical code is based on the coupled mode theory and the rate equations model. In particular, it includes the modal distribution of the optical waves in both tapered fiber and microsphere, and takes into account the most relevant active phenomena in Er 3þ -doped chalcogenide glasses, such as the absorption rates at both pump and signal wavelengths, the stimulated emission rate at signal wavelength, the amplified spontaneous emission noise, the lifetime and branching ratios of the considered energy levels, the ion-ion energy transfers, and the excited state absorption.…”

Radiation hardening of optical fibers and fiber sensors for space applications: recent advances

“…THE HARDENING-BY-SYSTEM APPROACH [19,22] A collaboration was initiated between our different research groups to determine the possible ways to improve the radiation hardness of these very radiation sensitive devices in order to authorize their integration in future space missions. Possible ways were to work on the improvement of the fiber itself -hardening by componentor to improve the resistance of the system by changing its design to reduce the impact of the fiber degradation on its performance -hardening by system -.…”

“…Additional tests were performed under proton exposure [15] and confirm that these HACC fibers and HACC-EDFA also resist to high fluences of 100 MeV protons without specific effects of the HACC structure in terms of dose deposition into the fiber core. In the future, the coupled simulation/experiments approach presented in [19] and detailed in §V will be applied to these amplifiers in order to enhance even more their radiation resistance by designing the amplifier parameters for optimal performances during the space mission.…”

Modeling of Whispering Gallery Modes for Rare Earth Spectroscopic Characterization

“…Moreover, a high number of microspheres, made of suitable rare earth doped glass, could be employed as punctual sensors for a number of different measurands; e.g. to obtain a radiation dose map, given that RIA (radiation induced absorption) and other spectroscopic parameters depend on the dose rate of the ionizing emissions, which are present in space, nuclear power plants, radio medicine and radio pharmacy plants [6]. Therefore, the aforesaid microsphere amplifiers could constitute an alternative to radiation distributed-fibersensors.…”