We report the observation of bistable polarization switching in a vertical-cavity surface-emitting laser under optical injection. The wavelength dependence of the switching is measured. It is found that this polarization switching is achieved through injection locking where both the wavelength and the polarization of the vertical-cavity laser are locked to the injected optical signal.

We show the polarization characteristics of gain-guided vertical-cavity surface emitting lasers are related to the temperature-dependent cavity optical resonance and laser gain spectral alignment. Simultaneous nearly degenerate orthogonal eigen polarization states are observed at and above lasing threshold. The partitioning of power between the linear polarization states is shown to depend on the relative spectral overlap of the cavity resonance of each state with the gain. Near the condition of cavity resonance/gain alignment, an abrupt switch in the dominant eigen polarization with a region of polarized output fluctuations is evident. Rotation of the eigen polarization directions relative to the crystal axes is also observed at temperatures where the gain is blue shifted from the cavity resonances.

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Abstract-We show that the partitioning of power into the two orthogonal eigen polarizations of infra-red gain-guided verticalcavity lasers depends upon the relative spectral overlap of the nondegenerate polarization cavity resonances with the laser gain spectrum. Furthermore, at the condition where the polarization resonances and the peak laser gain are aligned, abrupt switching of power between the eigen polarizations is observed as the gain sweeps through the polarization resonances. The gain-dependence of the polarization requires spectral splitting between the eigen polarizations, which is found to be strongly influenced by local strain. The polarization of the fundamental and higher-order spatial modes can be selected and maintained for all InGaAs vertical-cavity lasers in a wafer simply by employing a 20 nm or greater blue-shift offset of the peak laser gain relative to the cavity resonances.

Supermodes of multiplestripe quantumwell heterostructure laser diodes operated (cw, 300 K) in an externalgrating cavity