This is a 1 Channel 1550 LC/UPC Optical Circulator, all within a single 1U 19'' rack mount package. It is a 3-port nonreciprocal passive component that transmits light in only one direction. The WDM CIRCULATOR supports 1550 wavelength. Circulators are used to increase transmission capacity of existing networks by converting bi-directional signals through a single fiber. This allows the transmission capacity of the network to be doubled without the need for deploying additional fibers, which has become increasingly expensive. They exhibit high isolation and low insertion loss. Circulators can be used alongside MUX/DEMUX devices, optical Add/Drop, and other applications. AddOn's MUX/DEMUX products are 100% RoHS compliant. Now you have a cost effective solution for all your network upgrade needs. With our Certification Test Program, we can guarantee your product will work right the first time.