The Advantest Q7750 is the first network optical analyzer to allow the accurate characterization of all passive WDM components with a single instrument. In contrast to RF network analyzers operating with opto-electric converters, Q7750 performs scans in the optical range. It contains a continuously tunable laser for determining the transmission, reflection and chromatic dispersion of the modules. This previously required the use of several instruments. As a result the user obtains a readout of level and delay values at optical wavelengths. This allows, for instance, the measurement of group delay for a wavelength splitter within a WDM channel.