Apparatus and methods for a combined optical modulator/photodetector are disclosed. A modulator chip is attached to a photodetector chip using a non-conductive epoxy or solder. The combined modulator/photodetector can be configured in at least two ways. In one configuration, the modulator is located on the upper surface of a chip that is attached, at its lower surface, to a photodetector containing chip. In another configuration, the modulator is located on the lower surface of the modulator chip, which is again attached at its lower surface to the pbotodetector chip. By combining the modulator and photodetector in the manner described above, they can be placed in a single package, resulting in reduced packaging costs versus a separately packaged modulator and a separately packaged photodetector. Moreover, feedback from the photodetector can used to optimize the operation of micromechanical optical modulators.