Methods and apparatus for alignment of TO cans with photodiodes on fiber-optic receptacles. The methods and apparatus make use of direct connections to photodiodes or connections to Received Signal Strength Indicator (RSSI) outputs to align TO cans in fiber-optic receptacles. An optical source, such as a laser diode, can be powered by a low-frequency or DC source. This optical source can direct light into the fiber-optic receptacle. The TO can is manipulated in a barrel of the fiber-optic receptacle. The current through the photodiode or the RSSI output is monitored to determine when light directed into the photodiode is at a maximum or above a predetermined threshold. The TO can is fixed in the barrel when the light directed into the photodiode is at the maximum or predetermined threshold.