OPTICAL MULTIPLEXING IS THE ART OF COMBINING MULTIPLE OPTICAL SIGNALS INTO ONE TO MAKE FULL USE OF THE IMMENSE BANDWIDTH POTENTIAL OF AN OPTICAL CHANNEL. IT CAN PERFORM ADDITIONAL ROLES LIKE PROVIDING REDUNDANCY, SUPPORTING ADVANCED TOPOLOGIES, REDUCING HARDWARE AND COST ETC. MULTIPLEXING IS A TERM USED TO REFER TO A PROCESS WHERE MULTIPLE ANALOG MESSAGE SIGNALS OR DIGITAL DATA STREAMS ARE COMBINED INTO ONE SIGNAL OVER A SHARED MEDIUM. A DEVICE THAT PERFORMS THE MULTIPLEXING IS CALLED MULTIPLEXER (MUX), AND A DEVICE THAT PERFORMS THE REVERSE PROCESS IS CALLED DEMULTIPLEXER (DEMUX)