Abstract

Vertical-cavity surface-emitting lasers (VCSELs)¹ have some unique characteristics in terms of polarization. In contrast to edge-emitting lasers, the orientation of polarization is not defined in the plane of the active region. In the early experiments we have experienced the following behaviors upon polarizations, (i) Two degenerate orthogonal polarization states with fundamental mode are sometimes observed near and above the threshold, (ii) With increasing the current higher-order transverse modes tends to lase with a polarization orthogonal to the principal polarization, (iii) Polarization switching between the orthogonal polarization modes exhibits a partition noise in the two polarization states.² Thus, it was pointed out that a single dominant polarization state must be selected for polarization-sensitive applications such as magneto-optic disks and coherent detection systems.³ Regarding the relative intensity noise (RIN) the increment due to mode competition between the transverse modes was reported.^4,5 In this paper we investigated the noise which comes from polarization fluctuations with and without transverse mode competition in InGaAs/GaAs VCSELs.

© 1995 IEEE