An apparatus includes an optical device to output a data-modulated optical signal, an electrical radio-frequency (RF) driver to drive the optical device with one or more RF drive signals, a photodetector to provide a measure of a light intensity output by the optical device, and an electronic controller. The electronic controller is configured to dither an amplitude of at least one of the one or more RF drive signals at a dithering frequency. The electronic controller is also configured to adjust one or more operation settings of at least one of the electrical RF driver and the optical device based on a component of the measure of a light intensity at the dithering frequency.