before the comb is delivered to a system under test a polarization controller or polarization scrambler 140 operates upon the combined comb downstream of mux 124 to align polarization in a controlled manner to optimize external modulation power and to control polarization dependent dispersion and polarization dependent loss a polarization scrambler generates all states of polarization in a certain time interval which averages out polarization dependent effects and identifies minimum and maximum transmission orientations by way of example a commercially available device that can be used as both a polarization alignment device and a polarization scrambler is the polarite ii model pcs 3x pc apc 7 which is available from general photonics a splitter 142 divides the optical pathway for the combined comb into a polarized output segment leading to polarizer 144 and a non polarized segment 146 the segment leading to polarizer 144 is in optical communication with an optical power measurement module 148 which monitors the power output in the combined comb at different polarization states optical connectors 150 and 152 are present to receive optical input from other sources external to the optical test system 100 such as a system power monitor 154 or a general purpose power monitor 156 the non polarized segment 146 is advanced by a splitter 158 or a series of such splitters leading to an output panel 160 including a plurality of optical connectors 162 and 164 the panel 160 may be provided on the front or rear of the optical.