Résumé
The spectral purity of laser radiation is a key point in the performance of coherent optical network. As 850nm VCSELs are being used in short distance interconnections, the evaluation of the frequency noise level is essential. Using a Fabry-Perot cavity as a frequency discriminator, the frequency noise spectrum is being investigated in the medium frequency and high frequency range (up to 1GHz). Frequency noise spectra show a 1/fn part in the medium frequency domain and a traditional white noise part in the high frequency domain. The aim of this paper is to present our measurements concerning 850nm-selectively-oxidized VCSELs and to investigate the different factors which have a quantitative influence on the frequency noise spectrum.