An apparatus for measuring optical power including a first multiplexer/demultiplexer to split/combine an optical signal including a first wavelength and second wavelength; a second multiplexer/demultiplexer to split/combine an optical signal including the first wavelength and the second wavelength; a first tap photodetector coupled to the first and second multiplexer/demultiplexers and to a first measurement device; and a second tap photodetector coupled to the first and second multiplexer/demultiplexers and to a second measurement device.