High Speed Characteristics of VCSELs
The high speed characteristics of Vertical Cavity Surface Emitting Lasers (VCSELs) for use in modern high bandwidth fiber optic networks is presented. An equivalent circuit model based on microwave network analyzer S 11 measurements is developed. The dynamic operation of multi-transverse mode VCSELs is also investigated. Experimentally, a laser with two orthogonally polarized modes is examined. We show that each of the transverse laser modes may have significantly different rise and fall times. A multimode rate equation model is used to predict the exact pulseshape for each mode. The laser gain is saturated by the total optical intensity, and the sum of the modal powers is shown to have a constant rise and fall time. The system performance in terms of the bit error rate is also investigated. We demonstrate that selective attenuation of the optical modes can lead to an increase in the bit error rate due to polarization partitioning noise.
High Speed Characteristics of VCSELs
