Noise and Signal modeling of various VCSEL structures

Current evolution in Datacoms and Gigabit Ethernet have made 850nm Vertical Cavity Surface Emitting Lasers (VCSEL) the most important and promising emitter. Numerous different structures have been growth, to obtain best current confinement and then to control the emitted light modal behavior. We have developed a small signal equivalent electrical model of VCSEL including Bragg reflectors, active area, chip connection and noise behavior. Easy to integrate with classical software for circuit studies, this model which is widely adaptable for different structures takes into account the complete electrical environment of the chip. An experimental validation for RF modulation up to 10 GHz has been realized on oxide confined VCSEL, demonstrating that the model could be used to get realistic values for the VCSEL intrinsic parameters. Including Langevin noise sources into the rate equations and using the same electrical analogy, noise current and voltage sources can be added to the model. It allows good prediction for the RIN function shape up to 10GHz for monomodal emitter.