Processing a received optical signal in an optical communication network includes equalizing a received optical signal to provide an equalized signal, demodulating the equalized signal according to an m-ary modulation format to provide a demodulated signal, decoding the demodulated signal according to an inner code to provide an inner-decoded signal, and decoding the inner-decoded signal according to an outer code. Other aspects include other features such as equalizing an optical channel including storing channel characteristics for the optical channel associated with a client, loading the stored channel characteristics during a waiting period between bursts on the channel, and equalizing a received burst from the client using the loaded channel characteristics.

Processing a received optical signal in an optical communication network includes equalizing a received optical signal to provide an equalized signal, demodulating the equalized signal according to an m-ary modulation format to provide a demodulated signal, decoding the demodulated signal according to an inner code to provide an inner-decoded signal, and decoding the inner-decoded signal according to an outer code. Other aspects include other features such as equalizing an optical channel including storing channel characteristics for the optical channel associated with a client, loading the stored channel characteristics during a waiting period between bursts on the channel, and equalizing a received burst from the client using the loaded channel characteristics.

An optical emitter-receiver module includes a light source, a photodetector and a fiber. The light source emits an emitted beam. The fiber includes a core and an optical axis. The fiber has an outer surface, inclined at an angle of 45° with respect to the optical axis, having a mirror. The fiber has a notch, extending to the core of the fiber and having a face having a dichroic filter for reflecting a received beam. The light source is arranged relative to the mirror so that the emitted beam is reflected by the mirror and transmitted in the fiber. The photodetector and the face of the notch are positioned so that the received beam reflected by the dichroic filter is directed towards the photodetector.

An optical emitter-receiver module includes a light source, a photodetector and a fiber. The light source emits an emitted beam. The fiber includes a core and an optical axis. The fiber has an outer surface, inclined at an angle of 45° with respect to the optical axis, having a mirror. The fiber has a notch, extending to the core of the fiber and having a face having a dichroic filter for reflecting a received beam. The light source is arranged relative to the mirror so that the emitted beam is reflected by the mirror and transmitted in the fiber. The photodetector and the face of the notch are positioned so that the received beam reflected by the dichroic filter is directed towards the photodetector.

A transmitter can include a laser operable to output an optical signal; a digital signal processor operable to receive user data and provide electrical signals based on the data; and a modulator operable to modulate the optical signal to provide optical subcarriers based on the electrical signals. A first one of the subcarriers carriers carries first TDMA encoded information and second TDMA encoded information, such that the first TDMA encoded information is indicative of a first portion of the data and is carried by the first one of the subcarriers during a first time slot, and the second TDMA encoded information is indicative of a second portion of the data and is carried by the first one of the subcarriers during a second time slot. The first TDMA encoded information is associated with a first node remote from the transmitter and the second TDMA encoded information is associated with a second node remote from the transmitter. A second one of the subcarriers carries third information that is not TDMA encoded, the third information being associated with a third node remote from the transmitter. A receiver and system also are described.

A transmitter can include a laser operable to output an optical signal; a digital signal processor operable to receive user data and provide electrical signals based on the data; and a modulator operable to modulate the optical signal to provide optical subcarriers based on the electrical signals. A first one of the subcarriers carriers carries first TDMA encoded information and second TDMA encoded information, such that the first TDMA encoded information is indicative of a first portion of the data and is carried by the first one of the subcarriers during a first time slot, and the second TDMA encoded information is indicative of a second portion of the data and is carried by the first one of the subcarriers during a second time slot. The first TDMA encoded information is associated with a first node remote from the transmitter and the second TDMA encoded information is associated with a second node remote from the transmitter. A second one of the subcarriers carries third information that is not TDMA encoded, the third information being associated with a third node remote from the transmitter. A receiver and system also are described.

A sensing system. In some embodiments, the system includes a first imaging radio frequency receiver, a second imaging radio frequency receiver, a first optical beam combiner, a first imaging optical receiver, a second optical beam combiner, and an optical detector array. The first optical beam combiner may be configured to combine optical signals of the imaging radio frequency receivers. The second optical beam combiner may be configured to combine the optical signals of the imaging radio frequency receivers, and the optical signal of the first imaging optical receiver.

A sensing system. In some embodiments, the system includes a first imaging radio frequency receiver, a second imaging radio frequency receiver, a first optical beam combiner, a first imaging optical receiver, a second optical beam combiner, and an optical detector array. The first optical beam combiner may be configured to combine optical signals of the imaging radio frequency receivers. The second optical beam combiner may be configured to combine the optical signals of the imaging radio frequency receivers, and the optical signal of the first imaging optical receiver.

A single-fiber bidirectional optical transmission apparatus, a wavelength division multiplexing device, and an optical transmission system, is disclosed. The single-fiber bidirectional optical transmission apparatus includes: a first single-light-source coherent optical transceiver, configured to: receive a first optical signal from a first multiplexer/demultiplexer, convert the first optical signal into a first electrical signal, and send the first electrical signal to a first client signal processing apparatus; and a second single-light-source coherent optical transceiver, configured to: receive a second electrical signal from the first client signal processing apparatus, convert the second electrical signal into a second optical signal, and send the second optical signal to the first multiplexer/demultiplexer. A wavelength of the second optical signal is different from a wavelength of the first optical signal.

A single-fiber bidirectional optical transmission apparatus, a wavelength division multiplexing device, and an optical transmission system, is disclosed. The single-fiber bidirectional optical transmission apparatus includes: a first single-light-source coherent optical transceiver, configured to: receive a first optical signal from a first multiplexer/demultiplexer, convert the first optical signal into a first electrical signal, and send the first electrical signal to a first client signal processing apparatus; and a second single-light-source coherent optical transceiver, configured to: receive a second electrical signal from the first client signal processing apparatus, convert the second electrical signal into a second optical signal, and send the second optical signal to the first multiplexer/demultiplexer. A wavelength of the second optical signal is different from a wavelength of the first optical signal.