Temperature-Stable, Energy-Efficient, and High-Bit Rate Oxide-Confined 980-nm VCSELs for Optical Interconnects

Abstract

We report 980-nm VCSELs that achieve temperature-stable, energy-efficient, and high-bit rate data transmission concurrently. Oxide-aperture-dependent static characteristics and high-speed modulation properties are analyzed at room temperature and also at high temperature. It is demonstrated that VCSELs with oxide-aperture diameters smaller than ∼5 μm are most suitable to achieve energy-efficient, temperature-stable, and high-bit rate operation concurrently. We demonstrate error-free data transmission (defined as a bit error ratio < 1 × 10 −12) at 38 Gb/s from 25 to 85 °C without any change of working point and modulation condition by using VCSELs with oxide-aperture diameters smaller than 5 μm. For VCSELs smaller than ∼7 μm, 42 Gb/s error-free data transmission at 25 °C is achieved. Record low energy dissipation at 85 °C is achieved with our ∼3 μm oxide-aperture diameter VCSELs. At room temperature, only 145, 147, and 217 fJ of dissipated heat energy per bit is needed for 35, 38, and 42 Gb/s error-free data transmission. Each of these bit rates is a record low heat dissipation for 980-nm VCSELs. Our VCSELs are especially well suited for very short reach (<2 m) optical interconnects in high-performance computers, for board-to-board and chip-to-chip input/output interfaces and data buses, and for on-chip integrated photonics.