Abstract: In an optical access network using an optical switching device, a 2×1 optical splitter in the uplink and downlink directions is eliminated to extend the transmission distance between the OLT and the ONU. An optical switching device includes a downlink optical switch element for switching a downlink optical signal sent by an OLT, an uplink optical switch element for switching an uplink optical signal sent by a plurality of ONU, an O/E for converting a downlink optical signal to a first electrical signal, an E/O for converting the first electrical signal to a downlink optical signal and inputting the downlink optical signal to the downlink optical element, an O/E for converting an uplink optical signal output from the uplink optical switch element to a second electrical signal, and an E/O for converting the second electrical signal to an uplink optical signal and sending the uplink optical signal to the OLT.

Abstract: To provide synchronizing methods, optical switch modules, center devices, remote devices, optical access systems, optical access networks, programs, and recording media in the optical access network which can give the connection start time of the upstream optical switching element of the optical switch module. To the optical switch module, ranging functions are provided and the center device OLU carries out ranging of the optical switch module OSM as is the case of ranging of the remote device ONU. The center device OLU transmits the difference between roundtrip time of the remote device ONU and roundtrip time of optical switch module OSM, which is the result of these rangings, to the optical switch module OSM, and the optical switch module OSM can obtain the contact start time of the upstream optical switching element by calculating the contact start time using the difference.

Abstract: An optical access network method, an optical access network and an optical switch for an optical access network, capable of solving all the three problems in the conventional GE-PON: transmission distance problem, security problem and communication interference problem. The optical access network comprises an OLT, a plurality of ONUs and one or more stages of optical switches, which are connected one another. In the direction from the OLT to the ONU, each frame (packet) transmitted from the OLT to one of the ONUs is checked so that only the destination ONU specified in the frame (packet) is connected to the OLT. In the direction from the ONU to the OLT, a control message transmitted from the OLT to one of the ONUs is checked so that only one ONU which has been given a transmission allowance from the OLT is connected to the OLT with respect to each frame (packet).

Abstract: In an optical access network using an optical switching device, a 2×1 optical splitter in the uplink and downlink directions is eliminated to extend the transmission distance between the OLT and the ONU. An optical switching device includes a downlink optical switch element for switching a downlink optical signal sent by an OLT, an uplink optical switch element for switching an uplink optical signal sent by a plurality of ONU, an O/E for converting a downlink optical signal to a first electrical signal, an E/O for converting the first electrical signal to a downlink optical signal and inputting the downlink optical signal to the downlink optical element, an O/E for converting an uplink optical signal output from the uplink optical switch element to a second electrical signal, and an E/O for converting the second electrical signal to an uplink optical signal and sending the uplink optical signal to the OLT.

Abstract: To provide synchronizing methods, optical switch modules, center devices, remote devices, optical access systems, optical access networks, programs, and recording media in the optical access network which can give the connection start time of the upstream optical switching element of the optical switch module. To the optical switch module, ranging functions are provided and the center device OLU carries out ranging of the optical switch module OSM as is the case of ranging of the remote device ONU. The center device OLU transmits the difference between roundtrip time of the remote device ONU and roundtrip time of optical switch module OSM, which is the result of these rangings, to the optical switch module OSM, and the optical switch module OSM can obtain the contact start time of the upstream optical switching element by calculating the contact start time using the difference.

Abstract: An optical access network method, an optical access network and an optical switch for an optical access network, capable of solving all the three problems in the conventional GE-PON: transmission distance problem, security problem and communication interference problem. The optical access network comprises an OLT, a plurality of ONUs and one or more stages of optical switches, which are connected one another. In the direction from the OLT to the ONU, each frame (packet) transmitted from the OLT to one of the ONUs is checked so that only the destination ONU specified in the frame (packet) is connected to the OLT. In the direction from the ONU to the OLT, a control message transmitted from the OLT to one of the ONUs is checked so that only one ONU which has been given a transmission allowance from the OLT is connected to the OLT with respect to each frame (packet).