Effects of transverse anisotropy on VCSEL spectra

Abstract
High resolution spectral measurements on a commercial VCSEL array are reported. The authors observe frequency splittings that result from birefringence, typically 3–22 GHz, and from transverse anisotropy between differently oriented first-order modes, typically 3–17 GHz. The spectral splittings between the various transverse modes are found to be independent of polarisation.