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Nonlinear effects in high-power double-clad Er3+/Yb3+ fiber lasers and amplifiers

Abstract : Over the last few years there has been a large increase in the output power required of optical sources. The introduction of double-clad Er3+/Yb3+ doped fibers in the design of lasers and amplifiers has made it possible to obtain much higher power, which was hardly conceivable a few years ago. We can now envisage applying this technology, which was initially used in telecom devices, to other fields like medical, laser cutting, laser branding, lidar, drilling, welding, etc. Due to the high powers used in these devices, the apparition of nonlinear effects is inevitable. Nonlinear effects cause interference or distortion which damage the quality of the signals. Thus, understanding nonlinearities is essential in order to find engineering guidelines which reduce them when designing new devices. This work presents a theoretical and experimental contribution to the study of nonlinear effects in high-power double-clad Er3+/Yb3+ doped fiber amplifiers and lasers, specially self-phase modulation and stimulated Brillouin scattering. Self-phase modulation has been studied for pulses shorter than 4 ps. After the experimental set-up, a simulation tool has been created using the nonlinear Schrödinger equation with gain. So as to obtain more powerful pulses than self-phase modulation enables, a chirped pulse amplification system has been set up. Pulses as short as 450 fs with more than 35 kW of peak power have been obtained. For large impulsions -more than 10 ns-, the maximum output power is limited by another nonlinear effect: stimulated Brillouin scattering. This effect has been studied experimentally and modelled by a five-coupled equation system. As well as for self-phase modulation, a simulation tool has been set up. Other effects, such as stimulated Raman scattering or parametric amplification have also been investigated.
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https://pastel.archives-ouvertes.fr/pastel-00000743
Contributor : Ecole Télécom Paristech <>
Submitted on : Monday, February 14, 2005 - 8:00:00 AM
Last modification on : Friday, July 31, 2020 - 10:44:07 AM
Long-term archiving on: : Friday, October 19, 2012 - 11:35:08 AM

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Elena Olmedo Herrero. Nonlinear effects in high-power double-clad Er3+/Yb3+ fiber lasers and amplifiers. domain_other. Télécom ParisTech, 2003. English. ⟨pastel-00000743⟩

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