Spectral Transfer of Coherence with fiber-based interferometer 

WE ARE LOOKING FOR A MASTER INTERN for 2021: Internship subject

Principal Investigator : Dr Fabien Kéfélian

Fundings : Provence-Alpes-Côte d'Azur region, First-TF network, Observatoire de la Côte d'Azur & Université de Nice

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Summary :The goal of this project is to investigate experimentaly the potential of fiber based large arm imbalence interferometer to transfer the coherence of a stable laser to a laser with a wavelength difference of several tens of nanometers.

Former investigator : Dr Frédéric Audo, FIRST-TF funded post-doctoral research fellow in 2016, Lin-Wei Yu, intern from SupOptique - Institut d'optique graduate school in summer 2016 

Current Results :

First experimental evidence of a white frequency noise floor due to the residual third order nonlinearity of an optical frequency discriminator in laser frequency stabilization 

We have developped a low noise system to measure the frequency noise floor of the locking of a laser ona  fiber-based large imbalence interferometer. Thanks to this experiment we have been able to detect a significant contribution of the third order residual nonlinearity of the Michelson interferometer at the 100 mHz/Hz^1/2 level. The white noise level measured is in good agreement with the result of a numerical simulation of the effect of the non-linear frequency discriminator.

This is to our knowledge the first time that the effect of the residual non linearity of an optical frequency discriminator for frequency stabilization is considered and experimentaly measured. This effect could set the limit of the spectral linewidth of a laser stabilized on an ultra-stable Fabry-Perot cavity.

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