Methods and apparatus for monitoring the power level of one or more optical emitters are provided. In some embodiments, optical signals from two or more optical emitters are directed at different regions of a photo detector. The photo detector may include two or more spaced contacts that are adapted to receive different contributions of photo current from each of the optical signals. By monitoring the photo currents in the two or more spaced contacts, a measure of the optical power of each of the optical signals may be determined.