106 Gbit/s PAM4 60-km fibre-amplifierless transmission using SOA assisted extended reach EML (AXEL)

We fabricated an electroabsorptive modulated laser with an integrated semiconductor optical amplifier (AXEL) with high modulated output and superior extinction characteristics. A record 60-km 106 Gbit/s PAM4 modulation transmission was successfully demonstrated by using the AXEL transmitter with high average output of 9.1 dBm.