A monolithic photonic integrated circuit includes a platform, a monolithic laser formed in/on the platform, and an electro-optic polymer modulator monolithically built onto the platform and optically coupled to the monolithic laser. The polymer modulator is optically coupled to the monolithic laser by waveguides including electro-optic polymer waveguides. The electro-optic polymer modulator and the electro-optic polymer waveguides including an electro-optic polymer core and top and bottom electro-optic polymer cladding layers. The electro-optic polymer core having an electro-optic coefficient (r33) greater than 250 pm/v, and a Tg 150° C. to 200° C., and the top and bottom electro-optic polymer cladding layers having a Tg approximately the same as the Tg of the electro-optic polymer core.