All-Optical Inverter Based on Polarization Switching in VCSELs Subject to Single and Dual Optical Injection

All-optical inversion in single-mode vertical-cavity surface-emitting lasers (VCSELs) under single-and dual-polarized optical injection is numerically analyzed. For single optical injection, turn-on delay of the parallel polarized power and spikes of the orthogonally polarized power are similar to those found when gain-switching a multimode semiconductor laser. We consider two different methods for all-optical inversion using dual-polarized optical injection. In the first (second) method, pulses of orthogonally (parallel) polarized light and a CW parallel (orthogonally) polarized beam are injected into the VCSEL. Similar switching times and extinction ratios are obtained with both methods. Faster operation with any of these two methods is obtained than for single injection. We show that both types of dual optical injection produce all-optical inversion and all-optical gating with similar characteristics. All-optical gating and inversion are achieved for a 2.5 Gb/s NRZ signal.