Optical Add-Drop Multiplexers, commonly known as OADMs, are vital components in optical communication networks. As shown in the figure below, an optical multiplexer combines multiple wavelength signals into a single optical fiber. This is a type of optical node, which is generally used for the formation and the construction. The OADM full form is Optical Add-Drop Multiplexer. As bandwidth demand continues to rise, OADMs have become essential in metro. With elevated cost for leasing fiber, service providers and neutral hosts need smart and cost-effective ways to maximise the number of services per fiber. In practice, most signals pass through the device, but some would be “dropped” by splitting them from the line.