This lecture covers the use of MEMS in fiberoptic telecommunication systems, focusing on modulation, demodulation, and the selection of spectral components at optical telecommunication wavelengths using MEMS spectrometers. It also discusses interference filters, tunable IR detectors, Fabry-Perot interferometers, rotating grating tunable filters, and variable optical attenuators. The instructor presents examples of MEMS-based optical cross-connects, tunable filters, and variable optical attenuators, highlighting their design, operating principles, and technical specifications. The lecture concludes with a summary of the applications of MOEMS in various domains, emphasizing the versatility and potential of optical MEMS technology.