| 摘要 |
A composite passive optical network is provided to remarkably reduce the number of necessary upstream light sources by making ONUs(Optical Network Units) create subcarriers and transmit them to an RN(Remote Node) through electrical lines and making the RN modulate the subcarriers and create upstream optical signals. A composite passive optical network consists of a CO(Central Office)(210), an RN(250), and a plurality of ONU groups(300-1-300-N). The CO(210) outputs downstream optical signals. The RN(250) executes wavelength division demultiplexing for the downstream optical signals inputted from the CO(210), performs power splitting for each multiplexed signal, and creates a plurality of downstream signals. Then, the RN(250) outputs the created downstream signals to the ONUs of each associated group(300-1-300-N), receives upstream subcarriers from the ONUs of each group(300-1-300-N), modulates them into upstream optical signals, and outputs them to the CO(210). Each of the ONUs of each group(300-1-300-N) obtains the downstream subcarriers of each associated group from an associated downstream optical signal inputted from the RN(250), filters the obtained downstream subcarriers, obtains an associated downstream subcarrier, and outputs an associated upstream subcarrier to the RN(250).
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