A distributed antenna system includes a multiple-input and multiple-output (MIMO) base station configured to output at least a first signal and a second signal. At least one master unit communicates with the MIMO base station. At least one remote unit communicates with the master unit. At least one antenna is coupled with the remote unit for receiving signals from the remote unit. A coupler element is configured for introducing a phase shift in a portion of at least the first MIMO signal and for combining the phase shifted first MIMO signal portion with a portion of the second MIMO signal and presenting the combined first and second MIMO signal portions at an output port of the coupler element. An antenna is configured for receiving the combined MIMO signal portions for transmission.

A relay device includes: a first port, a plurality of second ports, a splitter configured to branch first optical signals input from the first port into the plurality of second ports; and a plurality of optical modulators configured to modulate shared carrier light by multiplexing the carrier light with a plurality of second optical signals with different frequencies input from the plurality of second ports and by inputting the multiplexed carrier light into a plurality of nonlinear optical mediums, and to transmit the carrier light to the first port.

An ONU requests a bandwidth of an uplink signal, and in accordance with this, an OLT calculates a time when the OLT transmits the uplink signal and a transmission duration time and performs an instruction, and a DBA cycle in which the ONU transmits the uplink signal in accordance with the instruction and a dynamic wavelength allocation cycle in which the OLT instructs wavelength switching, and the ONU switches the wavelength and belongs to a different LC are separated. While the ONU switches the wavelength, the DBA cycles can be performed plural times in the ONU whose wavelength is not switched, the switching of the wavelength is confirmed after the wavelength has been switched, and then DBA operation is performed at the switched wavelength.

A method for detecting an optical network unit (ONU) in a passive optical network (PON), an ONU, a PON and an optical line terminal (OLT) are disclosed. In an embodiment the method include detecting an ONU identity code in an open uplink empty window or an empty timeslot, wherein the ONU identity code is a specific code stream sequence of the ONU that identifies a single ONU of the plurality of ONUs included in the PON system during the open uplink empty window or the empty timeslot and determining that the single ONU corresponding to the ONU identity code is a rogue ONU according to the ONU identity code.

A system and method for performing an in-service optical time domain reflectometry test, an in-service insertion loss test, and an in-service optical frequency domain reflectometry test using a same wavelength as the network communications for point-to-point or point-to-multipoint optical fiber networks while maintaining continuity of network communications are disclosed.

Example embodiments describe an optical line terminal, OLT, configured to perform determining a fragmentation allocation for respective ONUs; and notifying, the respective ONUs, of the fragmentation allocation. Other example embodiments relate to an optical network unit, ONU, configured to perform receiving, from the OLT, fragmentation allocation for fragmenting one or more packets; processing the packets in accordance with the fragmentation allocation to obtain fragmented and unfragmented packets; and forwarding, to the OLT, the fragmented and unfragmented packets in accordance with the dynamic upstream allocation map.

A coherent passive optical network includes a downstream transceiver and first and second upstream transceivers in communication with an optical transport medium. The downstream transceiver includes a downstream processor for mapping a downstream data stream to a plurality of sub-bands, and a downstream transmitter for transmitting a downstream optical signal modulated with the plurality of sub-bands. The first upstream transceiver includes a first local oscillator (LO) for tuning a first LO center frequency to a first sub-band of the plurality of sub-bands, and a first downstream receiver for coherently detecting the downstream optical signal within the first sub-band. The second upstream transceiver includes a second downstream receiver configured for coherently detecting the downstream optical signal within a second sub-band of the plurality of sub-bands. The downstream processor dynamically allocates the first and second sub-bands to the first and second transceivers in the time and frequency domains.

A system and method for performing an in-service optical time domain reflectometry test, an in-service insertion loss test, and an in-service optical frequency domain reflectometry test using a same wavelength as the network communications for point-to-point or point-to-multipoint optical fiber networks while maintaining continuity of network communications are disclosed.

The present disclosure relates to an optical line terminal that can be used in an optical fiber access system based on passive optical networks. The present disclosure further relates to a PON system; in particular the optical line terminal can be configured such that colourless components can be employed in a PON system using the optical line terminal and such that wireless communication can be directly employed in a PON system. One embodiment relates to an optical line terminal for a passive optical network, comprising at least a first transmitter for generating a time division multiplexed (TDM) optical carrier signal, said first transmitter comprising a first time lens optical signal processor configured to convert the TDM optical carrier signal to an wavelength division multiplexed (WDM) optical carrier signal for distribution to a plurality of users/ONUs, at least a second transmitter for generating a wavelength division multiplexed (WDM) downstream optical data signal for distribution to said plurality of users/ONUs, and at least one receiver for receiving and processing an upstream signal from said users.

The present disclosure relates to an optical line terminal that can be used in an optical fiber access system based on passive optical networks. The present disclosure further relates to a PON system; in particular the optical line terminal can be configured such that colourless components can be employed in a PON system using the optical line terminal and such that wireless communication can be directly employed in a PON system. One embodiment relates to an optical line terminal for a passive optical network, comprising at least a first transmitter for generating a time division multiplexed (TDM) optical carrier signal, said first transmitter comprising a first time lens optical signal processor configured to convert the TDM optical carrier signal to an wavelength division multiplexed (WDM) optical carrier signal for distribution to a plurality of users/ONUs, at least a second transmitter for generating a wavelength division multiplexed (WDM) downstream optical data signal for distribution to said plurality of users/ONUs, and at least one receiver for receiving and processing an upstream signal from said users.