A system and method for generating communications waveforms that can operate in congested frequency spaces and in applications in which the receiver is moving with respect to the transmitter is provided. In one or more examples, each symbol to be encoded and transmitted is converted into a sequence of frequency chirps. The sequence of frequencies used by the sequence of chirps is based on the symbol that is to be encoded. Each chirp can have a center frequency, and the frequency can be swept over the duration of the chirp. In this way each chirp can have a varying frequency over the duration of the chirp, but the phase of the chirp can be continuous throughout the duration of the chirp. The bandwidth and sweep rate of the chirp can be based on the expected maximum velocity of the receiver and the transmitter relative to one another.

A system and method for generating communications waveforms that can operate in congested frequency spaces and in applications in which the receiver is moving with respect to the transmitter is provided. In one or more examples, each symbol to be encoded and transmitted is converted into a sequence of frequency chirps. The sequence of frequencies used by the sequence of chirps is based on the symbol that is to be encoded. Each chirp can have a center frequency, and the frequency can be swept over the duration of the chirp. In this way each chirp can have a varying frequency over the duration of the chirp, but the phase of the chirp can be continuous throughout the duration of the chirp. The bandwidth and sweep rate of the chirp can be based on the expected maximum velocity of the receiver and the transmitter relative to one another.

Aspects of the disclosure provide for methods and systems for feedback control of mode MUX and DEMUX. An aspect of the disclosure provides for a method associated with a mode MUX. The method includes modulating each WDM signal of a first set of WDM signals with a pilot tone of different frequency. The method further includes spatially multiplexing the first set of WDM signals to generate a multi-mode signal. The method further includes detecting the pilot tones from the multi-mode signal. The method further includes tuning the mode MUX based on the detecting. Another aspect of the disclosure provides for a method associated with a mode DEMUX. The method includes spatially demultiplexing a multi-mode signal into a set of WDM signals. The method further incudes detecting pilot tones from the set of WDM signals and tuning the mode DEMUX based on the detecting.

Optical transmission system transmits WDM signal from first node to second node via optical fiber. The optical transmission system includes: first OCM that detects optical power of each wavelength channel of the WDM signal in the first node; second OCM that detects optical power of each wavelength channel of the WDM signal in the second node; first processor that calculates linear SNR of each wavelength channel based on the optical power of each wavelength channel detected by the second OCM; second processor that calculates non-linear SNR of each wavelength channel based on the optical power of each wavelength channel detected by the first OCM; third processor that calculates GSNR for each wavelength channel using the linear SNR and the non-linear SNR; and fourth processor that controls transmission power of each wavelength channel of the WDM signal based on the GSNR of each wavelength channel.

A fiber-optic communication apparatus includes an optical monitor that monitors a WDM signal in. which optical signals of multiple channels are multiplexed, a processor that calculates a control value for controlling an optical power of the WDM signal, based. on a power spectrum detected by the optical monitor, in a unit interval of frequency narrower than a channel bandwidth of the WDM signal, and an optical power adjusting mechanism that adjusts the optical power of the WDM signal in the unit interval of frequency based on the control value.

An apparatus includes an optical source of an optical wavelength carrier, an optical modulator to receive the optical wavelength carrier, and an optical data receiver. The optical data modulator is configured to produce, from the optical wavelength carrier, an optical signal to carry separate data on different first and second components thereof in individual modulation periods during data transmission and to carry a training sequence on one of the components during time slots for calibration. The first component is relatively phase offset from the second component in the optical signal. The optical data modulator alternates the one of the components between the first and second components over the time slots for calibration. The optical receiver is connected to receive a portion of the optical signal and to temporally interleave a measurement of a characteristic of the first component and a measurement of a characteristic of the second component over the time slots for calibration. The optical receiver is configured to feedback information to the optical data modulator based on the measured characteristics. The optical data modulator is configured to reduce an imbalance between the two components of the optical carrier during data transmission based on the information.

A data management structure (1a) on board a transportation device, incorporating a cabin (100) provided with seats (110), includes a data resource block (210) incorporating audiovisual transmission system units (211 to 213), outward communication systems (100) and/or cabin systems, a standardised data distribution architecture (10a), and devices (E1 to E4) for operating said systems. In the structure (1a), the standardised architecture (10a) includes a concentration box (11) for the bidirectional transfer, on the one hand, of base signals with the resource block (210) and, on the other hand, optical signals with the devices (E1 to E4) of the cabin (100) on at least one optical fibre (2, 3; 2a, 2′a; 2b). This concentration box (11) houses units for processing (211 to 213) by signal switching, bidirectional conversion into optical signals, and optical signal management by wavelength allocation and distribution of downstream (F1) and upstream (F2) optical flows. This concentration box (11) is connected to the devices (E1 to E4) of said systems via intermediate boxes (30, 40) also housing processing units (111 to 113) according to the devices (E1 to E4) to which they are connected.

An example system includes a hub transceiver and a plurality of edge transceivers. The hub transceiver is operable to determine a plurality of optical subcarriers available for assignment by the hub transceiver to the plurality of the edge transceivers for use in communicating over an optical communications network, and assign, to each of the edge transceivers, a respective subset of the optical subcarriers. Each of the subsets of the optical subcarriers includes a respective data optical subcarrier for transmitting data over the optical communications network. At least one of the subsets of the optical subcarriers includes one or more respective idle optical subcarriers. The hub t transceiver is also operable to transmit to each of the edge transceivers, an indication of the respective subset of the optical subcarriers assigned to the edge transceiver.

An optical demultiplexer 40 includes: a plurality of optical gate switches 41a to 41n configured to transmit, when being turned on, and to block, when being turned off, a multiplexed optical signal obtained by multiplexing optical signals of a plurality of wavelengths by time-division multiplexing or wavelength-division multiplexing in addition to time-division multiplexing; and a cAWG 42 including a plurality of input ports and a plurality of output ports and configured to input the multiplexed optical signal transmitted through the optical gate switches 41a to 41n from the plurality of input ports, demultiplex the input multiplexed optical signal for each wavelength, and cycle and output the demultiplexed optical signals from the plurality of output ports in a predetermined order.

The present disclosure provides example wavelength selective switch (WSS), wavefront control element, and integrated liquid crystal on silicon (LCoS). One example WSS includes an input port fiber array, a demultiplexing/multiplexing grating group, an output port fiber array, and a beam deflection component group including two beam deflection components and at least one wavefront control element located between the demultiplexing/multiplexing grating group and the beam deflection component group or integrated with the LCoS. At least one beam deflection component is a LCoS. The input port fiber array receives multi-wavelength optical signals. The demultiplexing/multiplexing grating group demultiplexes and outputs the multi-wavelength optical signals. The beam deflection component group deflects the multi-wavelength optical signals to the demultiplexing/multiplexing grating group. The demultiplexing/multiplexing grating group multiplexes the multi-wavelength optical signals to the output port fiber array. The wavefront control element and the LCoS jointly modulate optical signals transmitted through N*M wavelength channels.