Abstract: A wavelength division multiplex transmitter for modulating light from a broadband light source and coupling modulated light to an optical waveguide for digital optical communications. The wavelength division multiplex transmitter includes a diffraction grating for receiving and diffracting light from a broadband light source. A first reflecting element receives diffracted light from the diffraction grating. A spectrally programmable spatial light modulator (SLM) receives reflected diffracted light from the reflecting element and selectively modulates a selected set of wavelengths of the reflected light. A lens receives the selected set of wavelengths and directs them into an optical waveguide for digital communication. This provides enhanced utilization of each wavelength within the broadband light source.