Polarization mode dispersion (PMD) can seriously degrade the quality of high-speed fiber-optic data transmission. High-speed transceivers must meet stringent standards for PMD tolerance. The DGD-1000 accurately and repeatably generates both high and low values of differential group delay (DGD) or first-order PMD. Both the DGD and PDL are very stable over time and wavelength within the performance band. This instrument is available in different versions to accommodate the need for different wavelengths and DGD ranges.