2.5-mW single-mode operation of 1.55-/spl mu/m buried tunnel junction VCSELs

We present 1.55-/spl mu/m wavelength buried tunnel junction InGaAlAs-InP vertical-cavity surface-emitting lasers with low threshold current and high efficiency. An improved mirror design is accomplished with high-reflective low-loss epitaxial InGaAlAs-InAlAs and hybrid dielectric CaF/sub 2/-ZnS-Au layer stacks, respectively. Lasers with aperture diameters of only around 5 /spl mu/m exhibit continuous-wave single-mode output powers at room temperature well beyond 2 mW. Threshold voltages and series resistances as low as 0.9 V and 30-40 /spl Omega/ have been measured. The spectral behavior shows excellent performance over the relevant current and temperature range.