Static and dynamic measurements are performed with GaAs oxide-confined vertical-cavity surface-emitting lasers (VCSELs), using multimode fibers with a core diameter of 50 and 62.5 m and different numerical apertures (NAs). They show that a small NA can have a severe impact on the eye opening and thus also on the bit-error rate. The measurements are analyzed with a spatiotemporal two-dimensional (2-D) multimode VCSEL model. The required parameter extraction for the model is verified with small-and large-signal measurements. The analysis shows that the change of the eye opening can be explained by the interaction between the mode-and the current-injection profile, carrier diffusion, and intermodal gain compression (IGC). IGC increases differences in the modal power distribution caused by the interaction between the mode profiles and the current-injection profile. Carrier diffusion is able to compensate these increased differences of the modal power distribution. Its impact, however, on dynamic changes caused by IGC is moderate.
© 2005 IEEE
Gion Sialm, Daniel Lenz, Daniel Erni, Gian-Luca Bona, Christian Kromer, Marc Xavier Jungo, Thomas Morf, Frank Ellinger, and Heinz Jckel, "Comparison of Simulation and Measurement of Dynamic Fiber-Coupling Effects for High-Speed Multimode VCSELs," J. Lightwave Technol. 23, 2318- (2005)