The VCSELs advantages (cost, bulkness, electronic integration, etc.) make it very attractive for datacom links as well as analogical links in on-board applications. We established first a rate equations system for monomodal AlGaAs VCSELs which includes intensity noise behaviour trough the Langevin forces. We then developed our model for multimodal VCSELs where we demonstrate that modal interactions due to spectral hole-burning generate a RIN level increase at low frequencies. Based on the small signal liearised monomodal and bi-modal rate equations,we have presented an eletrical equivalent circuit including equivalent noise current and voltage sources. The development of a low-power noise measurement setup for either VCSELs under probes or pigtailed VCSELs has allowed the noise characterization and models validation for various oxide-aperture VCSELs structures, on a wide frequency range up to 10 GHz. Finally, the development of rate equations, taking into account the non-linear behaviour of electron-photon interactions in the active area, has allowed the validation of the low-frequency intenisty noise up-conversion to RF carrier modelling. Characterisations of translated noise from 10 Hz to 10 MHz from the reference signal transmitted by a VCSEL based optical link have validated our spectral purity degradation model.
