Direct QAM-OFDM Encoding of an L-band Master-to-Slave Injection-Locked WRC-FPLD Pair for 28 × 20 Gb/s DWDM-PON Transmission

The 560 Gb/s (20 Gb/s × 28 channels) DWDM-PON with 16 quadrature amplitude modulation (QAM) orthogonal frequency division multiplexing (OFDM) transmission over 25-km SMF by using the master-to-slave injection-locked weak-resonant-cavity Fabry-Perot laser diode (WRC-FPLD) pair is demonstrated. After master-to-slave injection-locking, the BER of the 16-QAM OFDM data stream under back-to-back and 25-km transmissions can be improved from 3.3 × 10^-3 to 2.1 × 10^-5 and from 1.4 × 10^-1 to 1.2 × 10^-3, respectively. With OFDM subcarrier pre-leveling, the BER of 16-QAM OFDM data transmitted by the master-to-slave injection-locked WRC-FPLD over 25-km transmission is further improved from 1.2 × 10^-3 to 2.1 × 10^-4, concurrently enabling the 28 channel transmissions at 20 Gb/s with BER below FEC-limit of 3.8 × 10^-3. The back-to-back transmission of pre-leveled 64-QAM OFDM data at 30 Gb/s under is also demonstrated to achieve FEC limited BER at receiving power of -6 dBm by using the main of the master-to-slave injection-locked slave WRC-FPLD. The partially coherent injection-locking of maser-to-slave WRC-FPLD pair is comparable with the coherent DFB injection-locked WRC-FPLD, which is capable of serving as the universal transmitters with competitive performance of a power penalty as low as 0.5 dB between WRC-FPLD-to-WRC-FPLD and DFB-to-WRC-FPLD.