Excess intensity noise originated from polarization fluctuation in vertical-cavity surface-emitting lasers

Abstract
We have observed an excess-intensity noise that is attributed to polarization fluctuations of InGaAs-GaAs vertical-cavity surface-emitting lasers (VCSELs). It was observed, for the first time, that the intensity noise increased remarkably by the polarization fluctuation even when the single transverse mode operation was maintained. This result indicates that it is necessary to control the polarization state of VCSELs as well as control the transverse modes for low-noise operations.