High Power Single Mode 1300-nm Superlattice Based VCSEL: Impact of the Buried Tunnel Junction Diameter on Performance

Abstract

High power single mode wafer-fused 1300-nm VCSELs with a gain region based on InGaAs/InAlGaAs short period superlattice are fabricated. An InP-based optical cavity and two AlGaAs/GaAs distributed Bragg reflector heterostructures were grown by molecular beam epita&#x00F5;y. The current and optical confinement is provided by a lateral-structured buried tunnel junction with etching depth of <inline-formula> <tex-math notation="LaTeX">$\sim 25$ </tex-math></inline-formula> nm. It is shown that optimal diameter of the buried tunnel junction for high-power single mode emission is <inline-formula> <tex-math notation="LaTeX">$\sim 5$ </tex-math></inline-formula>-<inline-formula> <tex-math notation="LaTeX">$6~\mu \text{m}$ </tex-math></inline-formula>. The VCSEL demonstrates more than 6 mW single mode continuous-wave power and a threshold current less than 1.5 mA at 20 &#x00B0;C. The output optical power exceeds 1 mW at 85 &#x00B0;C. A -3dB modulation bandwidth up to 8 GHz and 6 GHz is obtained at 20 &#x00B0;C and 85 &#x00B0;C, respectively. The gain coefficient of <inline-formula> <tex-math notation="LaTeX">$\sim 650$ </tex-math></inline-formula> cm^&#x2212;1 and the transparency current density of <inline-formula> <tex-math notation="LaTeX">$\sim 630$ </tex-math></inline-formula> A/cm² are estimated at zero gain-to-cavity detuning (\sim 60 &#x00B0;C). The ultimate low internal optical losses about 0.08 &#x0025; per round-trip (distributed losses &#x007E;3.2 cm^&#x2212;1) at 20 &#x00B0;C and 0.13 &#x0025; per round-trip (distributed losses &#x007E;5.5 cm^&#x2212;1) at 100 &#x00B0;C were obtained.