In this paper, we perform a comparison of three modulation formats: NRZ, duo binary and DMT in combination with the state of the art 850 and 910nm VCSELs for their application in short reach high speed optical links. The system for NRZ and DB utilizes feasible for deployment equalization including a 9-tap finite impulse response filter and raised cosine filtering in the transmitter and a 7-tap UI-spaced feed forward equalizer in the receiver. The 100 Gbit/s net link with DB modulation can be realized without applying receiver equalization. For DMT the highest gross data rate of 224 Gbit/s/lambda is achieved.
We report high-frequency polarization self‐modulation (PSM) in high speed vertical-cavity surface emitting lasers (VCSELs) connected to the stress-induced birefringence in oxide-confined aperture VCSELs. Polarization oscillations up to 45 GHz were captured. We analyze the far and the near field of the device and show how the fiber-coupling conditions induce optical feedback, affect emission properties of the device and influence the polarization switching phenomenon. In conditions where the PSM was suppressed, we demonstrate NRZ high-speed multi-mode fiber data transmission up to 90 Gbit/s.