Real time noise and wavelength correlations in octave-spanning supercontinuum generation

J M Dudley,T Godin,M Zghal,A Ben Salem,F Dias,L Larger,A Kudlinski,G Genty,A Mussot,T Sylvestre,B Wetzel

doi:10.1364/oe.21.018452

Abstract

We use dispersive Fourier transformation to measure shot-to-shot spectral instabilities in femtosecond supercontinuum generation. We study both the onset phase of supercontinuum generation with distinct dispersive wave generation, as well as a highly-unstable supercontinuum regime spanning an octave in bandwidth. Wavelength correlation maps allow interactions between separated spectral components to be identified, even when such interactions are not apparent in shot-to-shot or average measurements. Experimental results are interpreted using numerical simulations. Our results show the clear advantages of dispersive Fourier transformation for studying spectral noise during supercontinuum generation.

Highlights

Fiber supercontinuum (SC) generation has been the subject of extensive previous research, the SC noise properties remain a subject of much current interest [1,2]
We use dispersive Fourier transformation to measure shot-toshot spectral instabilities in femtosecond supercontinuum generation. We study both the onset phase of supercontinuum generation with distinct dispersive wave generation, as well as a highly-unstable supercontinuum regime spanning an octave in bandwidth
Our results show the clear advantages of dispersive Fourier transformation for studying spectral noise during supercontinuum generation

Summary

Introduction

Fiber supercontinuum (SC) generation has been the subject of extensive previous research, the SC noise properties remain a subject of much current interest [1,2]. We report experimental results in two regimes of near-infrared SC generation using a femtosecond Ti:Sapphire system: at low power where we see distinct spectral features of pump pulse nonlinear spectral broadening and dispersive wave generation; and at a higher power where we generate an octave-spanning spectrum that exhibits very significant shotto-shot fluctuations [10]. In this latter regime, we show that the wavelength correlation map retains signatures of the underlying nonlinear spectral broadening, even though these are not apparent in the average spectrum or shot-to-shot spectral measurements. Our results clearly highlight the significant insight that can be obtained using the dispersive FT for ultrafast spectral measurements

Methods

Results

Conclusion