1550Â nm VCSEL-based 10Â Gb/s optical NRZ signal transmission over 20Â km SMF using RSOA gain saturation

A method for a 1550 nm vertical cavity surface emitting laser (VCSEL)-based 10 Gb/s optical non-return to zero (NRZ) signal transmission over 20 km single mode fiber (SMF) using reflective semiconductor optical laser amplifier (RSOA) gain saturation is presented. The optical signal distortion of 10 Gb/s optical NRZ signals caused by the inherent frequency chirp of the VCSEL and the chromatic dispersion of SMF were investigated through numerical simulations and experiments. For 20 km transmission over SMF, VCSEL-based 10 Gb/s optical NRZ signals were severely distorted and '1' bit signals had different amplitudes with respect to their bit patterns. The gain saturation of RSOA can equalize the different amplitudes of '1' bit signals and can mitigate the optical pulse distortion after 20 km transmission over SMF. The experimental results showed that VCSEL-based 10 Gb/s optical NRZ signals can achieve a bit error rate (BER) of 10-9 with a 2.4 dB dispersion penalty for 20 km transmission of SMF with RSOA gain saturation.