This letter reports a cost-effective transmitter solution for future generations of long reach passive optical networks (PONs). It is based on the direct adaptive orthogonal frequency division multiplexing modulation of a hybrid III/V-on-silicon laser. Because of low-noise and good linearity of the hybrid laser, modulation formats as high as 32-quadrature amplitude modulation are achieved. Data-rates of 21.5 and 12.4 Gb/s are demonstrated, respectively, in optical back-to-back and 50 km single-mode fiber (SMF)-link free from amplifiers, while on-off keying transmission is limited to at 20 km SMF. The proposed solution stands as a cost-effective solution for next-generation time and wavelength division multiplexing PONs with extended reach, as the hybrid laser can further be made tunable.