1300-nm wafer-fused VCSELs with InGaAs/InAlGaAs superlattice-based active region

Abstract

The paper presents the results of the research and development of 1300-nm vertical-cavity surface-emitting lasers, fabricated by wafer fusion technique for hybrid integration of an InAlGaAs/InP optical cavity with two AlGaAs/GaAs distributed Bragg reflectors using molecular-beam epitaxy. The active region is based on InGaAs/InAlGaAs superlattice, while current and optical confinement is provided by n⁺⁺-InGaAs/p⁺⁺-InGaAs/p++-InAlGaAs buried tunnel junction (BTJ). The proposed device design results in low internal loss (about 3.2 cm^-1 at 20 °C). The devices with BTJ diameter of 5 μm demonstrate a stable single-mode lasing with threshold current less than 1.3 mA and output optical power more than 6 mW and operation in a wide temperature range. The measured -3 dB bandwidth is more than 8 GHz at 20 °C and about 5.5 GHz at 85 °C, the eye diagrams are open with a bit rate up to 20 Gbps using nonreturn-to-zero (NRZ) modulation standard. Using 5-tap feedforward equalizer, the NRZ transmission at 25 Gbps has been demonstrated up to 5km single-mode fiber.