Photodarkening mitigation in Yb-doped fiber lasers by 405 nm irradiation

We investigate the impact of 405 nm radiation on photodarkening evolution in Yb-doped fiber. Simultaneous photodarkening and photobleaching effects induced by 976 nm and 405 nm radiations respectively were investigated in a 1070 nm laser

Photodarkening in Yb-doped Al-silicate fibers: Investigation, modelling and mitigation

In this paper we review our work on study of Photodarkening in Yb-doped Al-silicate base. We propose a measurement set-up and we investigate the possibility of Photodarkening mitigation by using visible light photons. We also report measurement of excited-state-absorption from excited Yb ions that plays a fundamental role in the photodarkening phenomenon

Photodarkening: Investigation, Measurement and Standards

This paper reports on the work done on photodarkening by our consortium. Particular emphasis is given to mitigate and measure photondarkening in high-quality Al-silicate fibers with high doping concentration

Gamma Radiation Tests of Radiation-Hardened Fiber Bragg Grating Based Sensors for Radiation Environments

In the framework of a KIC InnoEnergy funded project radiation-hardened Fiber Bragg Gratings (FBG) are developed to withstand high levels of radiation dose at high temperatures for their implementation in temperature- and strain sensors for nuclear facilities, accelerators or space. This paper presents gamma radiation test results obtained at room and elevated temperature in hardened FBGs as well as in the optical fibers used for their production. It is shown that radiation-induced Bragg wavelength shift (BWS) is below ±2 pm corresponding to ±0.2°C and does not influence the sensor performance even after a total dose of 200 kGy and operating temperature up to 350°C