850-nm Single-Mode Vertical-Cavity Surface-Emitting Lasers for 40 Gb/s Error-Free Transmission up to 500 m in OM4 Fiber

A single-mode (SM) vertical-cavity surface-emitting laser (VCSEL) constructed using a multi-oxidation structure was demonstrated. With the help of an undoped bottom mirror for reduction of optical absorption, the SM-VCSEL possessed a threshold current of 0.6 mA. A pure single mode is observed at an operating current of 4 mA. For back-to-back transmission, the maximum bandwidth is 26.6 GHz, and the highest bit-rate is 48 Gb/s for on-off keying modulation. Under single-mode operation, 40 Gb/s error-free transmission up to 500 m in OM4 fiber was achieved in this work.