Advancing VCSEL technology for short reach data links

Development of 850 nm VCSEL for optical interconnects continues with advances in modeling and device fabrication. The nonlinear large-signal response of a directly modulated laser is derived from rate equations. The resulting analytical expression exhibits the unequal rise and fall time in square wave response, and eye skew observed in PAM4 modulation. Demand for higher data rates and reduced power consumption will persist as long as the buildout of AI/ML networks lasts. The performance of VCSEL-based links at 212.5 Gb/s and feasibility of low power linear links at 106.25 Gb/s per lane is discussed.