A passive optical coupler having a number of input and output ports, used in network applications. Note: An optical signal introduced into any input port is distributed to all output ports. Because of the nature of the construction of a passive star coupler, the number of ports is usually a power of 2; i.e., two input ports and two output ports (a "two-port" coupler, customarily called a "directional coupler,"or "splitter"); four input ports and four output ports (a "four-port" coupler); eight input ports and eight output ports (an "eight-port" coupler); etc.