The 428 Series Multi-Wavelength Meter simultaneously measures wavelength, power, and OSNR in order to fully characterize DWDM components and DWDM transmission systems. The model 428 combines high accuracy and exceptional reliability to achieve the most meaningful test results. Straightforward operation and rugged design satisfy the needs of both the R&D scientist and the manufacturing engineer. The 428 Series Multi-Wavelength Meter combines proven Michelson interferometer-based technology with fast Fourier transform analysis. This results in the ability to measure the wavelength and power of up to 250 discrete optical signals. In addition, the 428 system can automatically calculate optical signal-to-noise ratio (OSNR) to greater than 40 dB.