Wavelength-division multiplexing in passive optical networks

An optical transmitter, for connection by way of a passive optical network to a plurality of optical receivers, including:

• signal transmission means for generating a plurality of optical signals having different respective wavelengths, each said optical signal carrying data, and wavelength-division-multiplexing the optical signals;
• and
• control information generation means for generating control information to be sent to said optical receivers to designate which of the optical signals of said plurality each receiver is to select to derive therefrom the data carried thereby, wherein the control information is changed dynamically in use of the network,
• the optical transmitter being adapted to send said control information to the optical receivers by way of said passive optical network;
• wherein said signal transmission means includes:
• a plurality of transmitter devices corresponding respectively to said optical signals, each transmitter device being connected to said information generating control means for receiving therefrom the data allocated by the control information generating means to its corresponding optical signal and being operable to modulate its corresponding optical signal with the allocated data;
• and
• wavelength-division-multiplexing combiner means coupled to each of said transmitter device for wavelength-division-multiplexing said optical signals.

A communications network including:

• an optical transmitter for generating a plurality of optical signals having different respective wavelengths, each said optical signal carrying data, and wavelength-division-multiplexing the optical signals;
• and
• a plurality of optical receivers connected to the optical transmitter by way of a passive optical network for receiving the wavelength-division-multiplexed optical signals, each receiver having wavelength selection means operable in dependence upon control information sent from the transmitter to the receiver concerned by way of said passive optical network to select one of the optical signals of said plurality, and also having detection means for processing the selected optical signal to derive therefrom the data carried thereby,
• wherein the control information is changed dynamically in use of the network;
• and,
• wherein said optical transmitter includes:
• a plurality of transmitter devices corresponding respectively to said optical signals, each transmitter device being connected to a transmission control means for receiving therefrom the data allocated by the transmission control is to its corresponding optical signal and being operable to modulate its corresponding optical signal with the allocated data;
• and
• wavelength-division-multiplexing combiner means coupled to each of said transmitter device for wavelength-division-multiplexing said optical signals.

A communications network including:

• an optical transmitter for generating a plurality of optical signals having different respective wavelengths, each said optical signal carrying data, and wavelength-division-multiplexing the optical signals;
• and
• a plurality of optical receivers connected to the optical transmitter by way of a passive optical network for receiving the wavelength-division-multiplexed optical signals, each receiver having wavelength selection means operable in dependence upon control information sent from the transmitter to the receiver concerned to select one of the optical of said plurality, and also having detection means for processing the selected optical signal to derive therefrom the data carried thereby, wherein said control information specifies only changes in optical signal selection to be made by said optical receivers;
• wherein said optical transmitter includes:
• a plurality of transmitter devices corresponding respectively to said optical signals, each transmitter device being connected to a transmission control means for receiving therefrom the data allocated by the transmission control means to its corresponding optical signal and being operable to modulate its corresponding optical signal with the allocated data;
• and,
• wavelength-division-multiplexing combiner means coupled to each of said transmitter device for wavelength-division-multiplexing said optical signals.

A communications network including:

• an optical transmitter for generating a plurality of optical signals having different respective wavelengths, each said optical signal carrying data, and wavelength-division-multiplexing the optical signals;
• and
• a plurality of optical receivers connected to the optical transmitter by way of a passive optical network for receiving the wavelength-division-multiplexing optical signals, each receiver having wavelength selection means operable in dependence upon control information sent from the transmitter to the receiver concerned by way of said passive optical network to select one of the optical signals of said plurality, and also having detection means for processing the selected optical signal to derive thereform the data carried thereby, wherein the control information relevant to a given optical receiver is carried as overhead information by all of the optical signals;
• wherein said optical transmitter includes:
• a plurality of transmitter devices corresponding respectively to said optical signals, each transmitter device being connected to a transmission control means for receiving therefrom the data allocated by the transmission control means to its corresponding optical signal and being operable to modulate its corresponding optical signal with the allocated data;
• and
• wavelength-division-multiplexing combiner means coupled to each of said transmitter device for wavelength-division-multiplexing said optical signals.

A communications network including:

• an optical transmitter for generating a plurality of optical signals having different respective wavelengths, each said optical signal carrying data, and wavelength-division-multiplexing the optical signals;
• and
• a plurality of optical receivers connected to the optical transmitter by way of a passive optical network for receiving the wavelength-division-multiplexed optical signals, each receiver having wavelength selection means operable in dependence upon control information sent from the transmitter to the receiver concerned to select one of the optical signals of said plurality, and also having detection means for processing the selected optical signal to derive therefrom the data carried thereby, wherein the control information is sent from the transmitter to the receiver concerned by way of said passive optical network and the control information relevant to a given optical receiver is carried as overhead information only by the optical signal currently selected by said given optical receiver;
• wherein said optical transmitter includes:
• a plurality of transmitter devices corresponding respectively to said optical signals, each transmitter device being connected to a transmission control means for receiving therefrom the data allocated by the transmission control means to its corresponding optical signal and being operable to modulate its corresponding optical signal with the allocated data;
• and
• wavelength-division-multiplexing combiner means coupled to each of said transmitter device for wavelength-division-multiplexing said optical signals.

A communications network including:

• an optical transmitter for generating a plurality of optical signals having different respective wavelengths, each said optical signal carrying data, and wavelength-division-multiplexing the optical signals;
• and
• a plurality of optical receivers connected to the optical transmitter by way of a passive optical network for receiving the wavelength-division-multiplexed optical signals, each receiver having wavelength selection means operable in dependence upon control information sent from the transmitter to the receiver concerned to select one of the optical signals of said plurality, and also having detection means for processing the selected optical signal to derive therefrom the data carried thereby, wherein the control information is sent from the transmitter to the receiver concerned by way of said passive optical network and said control information is transmitted from said optical transmitter to said optical receivers by a further optical signal having a wavelength different from that of each of said optical signals of said plurality, that is wavelength-division-multiplexed with the optical signals of said plurality;
• wherein said optical transmitter includes:
• a plurality of transmitter devices corresponding respectively to said optical signals, each transmitter device being connected to a transmission control means for receiving therefrom the data allocated by the transmission control means to its corresponding optical signal and being operable to modulate its corresponding optical signal with the allocated data;
• and
• wavelength-division-multiplexing combiner means coupled to each of said transmitter device for wavelength-division-multiplexing said optical signals.

An optical transmitter for connection by way of a passive optical network to a plurality of optical receivers, including:

• different signal transmission means for generating a plurality of optical signals having different respective wavelengths, each said optical signal carrying data and wavelength-division-multiplexing the optical signals;
• and
• control information generation mews for generating control information to be sent to said optical receivers to designate which of the optical signals of said plurality each receiver is to select to derive therefrom the data carried thereby;
• wherein the optical transmitter is adapted to send said control information to the optical receivers by way of sad passive optical network, and further includes:
• overhead information adding means connected to said control information generation means for receiving therefrom the control information generated thereby and also connected to said signal transmission men for causing the signal transmission means to include the control information as overhead information in the optical signals of said plurality;
• and
• selection storing means for storing the respective current optical-signal selections made by the optical receivers;
• said overhead information adding means being operable, when control information is to be transmitted to one of said optical receivers, to determine from the stored current optical-signal selections the optical signal of said plurality that is currently selected by the optical receiver, and to cause the control information to be carried as overhead information only by the determined optical signal;
• and
• wherein said signal transmission means includes:
• a plurality of transmitter devices corresponding respectively to said optical signals, each transmitter device being connected to said control information generation means for receiving thereform the data allocated by the control information generation means to its corresponding optical signal and being operable to modulate its corresponding optical signal with the allocated data;
• and
• wavelength-division-multiplexing combiner means coupled to each of said transmitter device for wavelength-division-multiplexing said optical signals.

An optical transmitter, for connection by way of a passive optical network to a plurality of optical receivers, including:

• signal transmission means for generating a plurality of optical signals having different respective wavelengths, each said optical signal carrying data, and wavelength-division-multiplexing the optical signals;
• and
• control information generation means for generating control information to be sent to said optical receivers to designate which of the optical signals of said plurality each receiver is to select to derive therefrom the data carried thereby,
• wherein the optical transmitter is adapted to send said control information to the optical receivers by way of said passive optical network,
• and wherein said signal transmission means include:
• a plurality of transmitter devices corresponding respectively to said optical signals, each transmitter device being connected to said transmission control means for receiving therefrom the data allocated by the transmission control means to its corresponding optical signal and being operable to modulate its corresponding optical signal with the allocated data;
• wavelength-division-multiplexing combiner means coupled to each of said transmitter devices for wavelength-division-multiplexing said optical signals;
• and
• a further transmitter device coupled to said control information generation means and also coupled to said wavelength-division-multiplexing combiner means and operable to generate a further optical signal, having a wavelength different from that of each of the optical signals of said plurality which further optical signal carries said control information.