Highly stable single polarization operation of GaInAs/GaAs vertical-cavitysurface-emitting laser on GaAs (311)B substrate under high-speed modulation

We have demonstrated a dynamically stable polarization mode GaInAs/GaAs ver tical-cavity surface-emitting laser (VCSEL) grown on a GaAs (311)B substrat e. The fabricated device exhibited a stable and single polarization under D C and high-speed modulation. Under DC operation, the orthogonal polarizatio n suppression ratio (OPSR) was larger than 30 dB. We measured the time-reso lved OPSR using square-wave modulation. it was found that the orthogonal mo de was suppressed even for the first peak of the relaxation oscillation wit h OPSR > 17 dB. In a 5 Gbps non-return-to-zero (NRZ) pseudo-random bit sequ ence (PRBS) modulation experiment, the OPSR was greater than 27 dB. These s table and single polarization characteristics were due not only to the anis otropic optical gain on a (311)B substrate, but also strained GaInAs/GaAs q uantum cells and the thin oxide layer which was employed in this experiment .