A wavelength-division-multiplexing (WDM) chip fabricated using the PPro-2 process is described. The chip is composed of three independently tunable lasers, which are connected by a passive waveguide optical combiner into a single waveguide leading into an optical output amplifier. Thus it provides three optical channels, each of which can be independently AM or FM modulated. All three channels are fed into a single waveguide that is readily coupled into a single-mode fiber. The output optical amplifier is used to compensate for losses that are mainly caused by the optical power combiner. The total output power is thus limited by the saturation power of the optical amplifier. Typically, a useful range of operation is up to approximately 1-2 mW/channel at the output.