Introduction of PLC Technology and Fabrication Processes

PLC is more known in the field of electronic technology. It is the acronym of the terminology ‘programmable logic controller’. However, in the field of optical communication, PLC is the acronym of another terminology, i.e. ‘planar lightwave circuit’, which is variable optical waveguide structures fabricated with integrated optics technologies. PLC technologies can implement functional devices as directional coupler (DC), Y-branch splitter, multimode interferometer (MMI), arrayed waveguide grating (AWG), optical interleaver (ITL), Mach-Zehnder (MZ) electro-optical modulator, thermo-optical variable optical attenuator (TO-VOA), thermo-optical switch (TO-SW), etc.