Monolithic transmitter photonic integrated circuit (TxPIC) with a traversely disposed output

A photonic integrated circuit chip comprising:

• a plurality of optical sources, each of the plurality of optical sources having a length extending in a first direction, each of the plurality of optical sources providing a corresponding one of a plurality of optical signals at a respective one of a plurality of wavelengths;
• an optical combiner having a plurality of inputs and an output, each of the plurality of inputs configured receive a corresponding one of the plurality of optical signals, the optical combiner configured to combine the plurality of optical signals into a multiplexed output signal and supply the multiplexed output signal at the output of the optical combiner;
• and
• an output waveguide having a first end portion, a second end portion, and a longitudinal axis extending through the first and second end portions, the first end portion of the output waveguide coupled to the output of the optical combiner and the second end portion of the output waveguide extending to a facet of the chip, the longitudinal axis of the output waveguide in the second end portion of the output waveguide extending in a second direction, the second direction being substantially perpendicular to the first direction.