A two-sectioned InAs/InP quantum dash laser structure is proposed and investigated as a monolithic broadband multimodal tunable laser with an integrated semiconductor optical amplifier. The optical power-injection current and spectral characteristics of the device at different operating conditions demonstrated a total wavelength tunability of ∼15.8  nm in the extended-L-band (∼1615 to ∼1630.8  nm) window with ∼2.0 times −3  dB bandwidth enhancement. Furthermore, due to the unique tunability mechanism of forward biasing the amplifier section, the device exhibits simultaneous wavelength tuning as well as optical amplification features, with an estimated gain of ∼8.5  dB affirmed by an increase in the wall-plug efficiency up to 6.8% from 3.9%, shown by its single-section counterpart. This demonstration paves a potential platform for the deployment of broadband quantum-dash laser-amplifiers as unified light sources in next-generation optical access networks.