A system for dynamically adjusting a bias voltage for a laser diode or a light emitting diode is provided. An output voltage of the laser diode is measured and a level of a supply voltage applied to the laser diode is adjusted to change the bias voltage to the laser diode to manage power usage and avoid saturation of the laser diode. Also, a junction temperature of a laser diode may be estimated by mapping a measured output voltage and known current to device characteristic data based on temperature and the supply voltage adjusted in order to bias the laser diode to compensate for a temperature change. Further, data indicating an intensity level of data to be rendered by the laser diode is used to adjust the second supply voltage to bias the laser diode in advance of rendering the data.