A novel architecture of DWDM-PON is proposed and demonstrated for downlink transmission of different data-rates of 622Mbps, 1Gbps, 1.25Gbps and 2.5Gbps simultaneously over a long-haul single mode fiber (SMF). The data rates are directly modulated by Fabry–Pérot laser diodes (FPLD), which are externally injection locked by asynchronous spontaneous emission (ASE) source. The transmission performances are checked by the bit error rate (BER), Quality (Q) factor and clear eye-diagrams. Since this proposed system consists of one ASE source, FPLDs and depends on the direct modulation technique, it reveals a prominent alternative with advantages in simplicity and cost.