Performance degradations of WDM systemsdue to laser and optical filter misalignments

Abstract
Laser and optical filter misalignment tolerances for WDM systems with two optical filters are almost the same at 2.5 Gbit/s and 10 Gbit/s per optical channel. For the three types of optical filters used, multilayer dielectric film optical filters have the highest misalignment tolerances, grating-based optical filters have lower tolerances, and multiple-path interferometer optical filters have the lowest tolerances. Using two grating-based optical filters, laser misalignments of about ±30 GHz for 25 GHz filter misalignments produce 1 dB system excess loss.