DWDM OADM ( DWDM/AD) modules are Dense Wavelength Division Multiplexing (DWDM) Optical Add and Drop Multiplexers (OADM). "Add" and "drop" here refer to the capability of the device to add one or more new wavelength channels to an existing multi-wavelength WDM signal, and to drop (remove) one or more channels, passing those signals to another network path. Using high performance filter technology, the DWDM/AD is a passive optical add/drop multiplexer designed to optically add/drop one or multiple DWDM channels into one or two fibers. It is an ideal solution for Metro-Core, Metro-Access and Enterprises, comprise a family of flexible, cost-effective solutions that expand the bandwidth capacity of existing fiber in point-to-point, ring, or bus configurations' applications. Add/drop channels are interfaced to any of Fiber-Mart DWDM transceivers on the equipment side, and we also provide optional port configurations such as: Monitor Port, 1310nm passband port and Express port according to customer request. Available in 100GHz or 200GHz (0.8/1.6nm), 19" Rack Mount, LGX module or Pigtailed ABS box packaging.