Polarisation anisotropy in asymmetric oxide aperture VCSELs

Strong polarisation discrimination is observed from asymmetric oxide-aperture vertical cavity surface emitting lasers (VCSELs). The polarisation state perpendicular to the longer direction of the slit-shaped oxide aperture dominates when the aperture width is <4 /spl mu/m. Generally, the mode size for TM polarisation is slightly less than that for TE polarisation, indicating polarisation-dependent scattering losses. A 1.4 /spl mu/m oxide aperture VCSEL gives a polarisation extinction ratio (PER) of up to 184.