The 228 Series Optical Wavelength Meter combines high accuracy and exceptional repeatability to achieve the most meaningful results for DWDM test applications. With a wavelength accuracy as high as ± 0.3 pm, the model 228 is the ideal instrument for precise wavelength characterization of tunable DWDM lasers, DFB lasers, and VCSELs. It can also be used to calibrate passive DWDM component test equipment such as optical spectrum analyzers. The 228 Series Optical Wavelength Meter uses a proven optical interferometer-based design to measure absolute wavelength of CW lasers to the highest accuracy available. Two versions are offered. The model 228A is used for the most demanding applications, measuring wavelength to an accuracy of ± 0.3 pm. For less exacting test requirements, the model 228B is a lower-priced alternative with an accuracy of ± 1.2 pm.