Skip to Main content Skip to Navigation

Combinaison cohérente dans une fibre multicœurs pour des applications LIDAR

Abstract : Coherent Lidars can measure wind speed at long distance, using the Doppler frequency shift induced by the movement of the back reflecting aerosols. Wind Lidars usually include a MOPFA (Master Oscillator Power Fiber Amplifier) made of a continuous oscillator, an intensity modulator and a fiber amplifier. The main objective of this thesis is the realization of an eye-safe, high peak power, pulsed MOPFA using an erbium-doped multicore fiber. Single frequency pulse amplification in fibers is limited by nonlinear effects due to tight beam confinement in the core. Multicore fibers can be seen as a very large core fiber, thus mitigating the nonlinear effects. The pulse to be amplified is divided and injected into all cores of the amplifying fiber using a spatial light modulator (SLM). The amplified output pulses are then recombined at the fiber output by a diffractive optical element (DOE). The coherent combination at fiber output requires independent control of phases at injection provided by a feedback loop based on the DOE zero order power. The peak power after combination is the sum of the peak powers reached in each of the cores.
Document type :
Complete list of metadata

Cited literature [82 references]  Display  Hide  Download
Contributor : ABES STAR :  Contact
Submitted on : Friday, June 9, 2017 - 5:25:09 PM
Last modification on : Saturday, June 25, 2022 - 10:24:42 PM
Long-term archiving on: : Sunday, September 10, 2017 - 1:30:16 PM


Version validated by the jury (STAR)


  • HAL Id : tel-01535940, version 1


Florian Prevost. Combinaison cohérente dans une fibre multicœurs pour des applications LIDAR. Optique [physics.optics]. Université Paris Saclay (COmUE), 2017. Français. ⟨NNT : 2017SACLO003⟩. ⟨tel-01535940⟩



Record views


Files downloads