A passive optical subscriber network is implemented only with passive optical components. The passiveness of the optical subscriber network makes it easier to operate and maintain the system. And it is easy to adapt the broad-band services without any change of the architecture in the future. We investigated the optical characteristics of passive optical components and the multiplexing technologies for passive optical subscriber networks. We suggested a model for passive optical subscriber networks and measured bit error rate (BER) of the testbed suggested. The measured results satisfied the system margin of 6 dB for $10^{-9}$ BER. When the WDM components were inserted into the system, the system margin was reduced to 5 dB. And this testbed showed the same good performances for both high and low temperature environments.
