25.78-Gb/s Operation of RSOA for Next-Generation Optical Access Networks

We report the 25.78-Gb/s operation of the reflective semiconductor optical amplifier (RSOA) for the next-generation optical access network. For this purpose, we develop a butterfly-packaged RSOA and minimize the electrical parasitics. As a result, the modulation bandwidth of RSOA is improved from 2.2 to 3.2 GHz (which is the fundamental limit imposed by the carrier lifetime). In addition, the slope of the RSOA´s frequency response curve is enhanced from -40 to -20 dB/decade. Using this butterfly-packaged RSOA, we have demonstrated the 25.78-Gb/s operation. The receiver sensitivity is measured to be -11 dBm with the help of the electronic equalization and forward-error-correction (FEC) techniques. To evaluate the possibility of implementing the 100-Gb/s passive optical network (PON) by using this RSOA and the coarse wavelength-division-multiplexing (CWDM) technique, we evaluate the BER performance at four different wavelengths in the C-band. The results show that the error-free transmission can be achieved in the wavelength range of 20 nm with a penalty less than 2 dB. Thus, we can realize the 100-Gb/s PON cost-effectively by utilizing the directly modulated RSOAs operating at 25 Gb/s.