An example system includes a hub transceiver and a plurality of edge transceivers. The hub transceiver is operable to transmit, over a first communications channel, a first message to each of the edge transceivers concurrently, including an indication of available network resources on an optical communications network. Each of the edge transceiver is operable to transmit, transmit, over a second communications channel, a respective second message to the hub transceiver including an indication of a respective subset of the available network resources selected by the edge transceiver for use in communicating over the optical communications network. Further, the edge transceiver is operable to receive, from the hub transceiver, a third message acknowledging receipt of a selection and a fourth message confirming an assignment of the selected subset of the available network resources to the edge transceiver.

An optical phased array (OPA) photonic integrated chip includes a plurality of array elements, a plurality of phase shifters, a plurality of combiners, and an edge coupler configured to couple to a single mode waveguide. The plurality of phase shifters includes a layer of phase shifters that has a phase shifter connected to each array element in the plurality of array elements. The plurality of combiners is configured to connect the plurality of phase shifters to the edge coupler. The plurality of combiners includes a first combiner that has a first output that is connected to a second combiner or the edge coupler, and a second output of the first combiner is connected to a photodetector. An in-phase light portion at the first combiner is output through the first output, and an out-of-phase light portion at the first combiner is output through the second output.

An optical phased array (OPA) photonic integrated chip includes a plurality of array elements, a plurality of phase shifters, a plurality of combiners, and an edge coupler configured to couple to a single mode waveguide. The plurality of phase shifters includes a layer of phase shifters that has a phase shifter connected to each array element in the plurality of array elements. The plurality of combiners is configured to connect the plurality of phase shifters to the edge coupler. The plurality of combiners includes a first combiner that has a first output that is connected to a second combiner or the edge coupler, and a second output of the first combiner is connected to a photodetector. An in-phase light portion at the first combiner is output through the first output, and an out-of-phase light portion at the first combiner is output through the second output.

An optical transmitter device includes a modulator of the Mach-Zehnder type that modulates the optical signal from an emitter and outputs modulated signals; and a phase controller that controls the phase difference of the modulator according to a setting phase amount. The device includes a controller, a sweeper, and an estimator. The controller controls the bias current of the emitter so that the power of the modulated signals detected at the output stage of the modulator during the optical shutdown becomes the target value during the optical shutdown. After the bias current is controlled, the sweeper performs constant-period sweeping of the phase of the modulator. The estimator estimates, while sweeping the phase, the transmission characteristics of the modulator from the power of the optical signal detected at the input stage of the modulator; and, from the estimated characteristics, calculates the optimum phase amount to be set in the phase controller.

An optical transmitter device includes a modulator of the Mach-Zehnder type that modulates the optical signal from an emitter and outputs modulated signals; and a phase controller that controls the phase difference of the modulator according to a setting phase amount. The device includes a controller, a sweeper, and an estimator. The controller controls the bias current of the emitter so that the power of the modulated signals detected at the output stage of the modulator during the optical shutdown becomes the target value during the optical shutdown. After the bias current is controlled, the sweeper performs constant-period sweeping of the phase of the modulator. The estimator estimates, while sweeping the phase, the transmission characteristics of the modulator from the power of the optical signal detected at the input stage of the modulator; and, from the estimated characteristics, calculates the optimum phase amount to be set in the phase controller.

The disclosed systems, structures, and methods are directed to a single-stage frequency-domain equalization (FDEQ) structure implemented on a processor, comprising a data preprocessing unit configured to concatenate received data samples in time-domain digital signals, transform the concatenated data samples in the time-domain digital signals to frequency-domain digital signals, and an adaptive equalizer comprising 2×2 multiple-input multiple output (MIMO) configured to compensate for non-time-varying fixed impairments and time-varying adaptive impairments in the frequency-domain digital signals.

The disclosed systems, structures, and methods are directed to a single-stage frequency-domain equalization (FDEQ) structure implemented on a processor, comprising a data preprocessing unit configured to concatenate received data samples in time-domain digital signals, transform the concatenated data samples in the time-domain digital signals to frequency-domain digital signals, and an adaptive equalizer comprising 2×2 multiple-input multiple output (MIMO) configured to compensate for non-time-varying fixed impairments and time-varying adaptive impairments in the frequency-domain digital signals.

A controller to communications between a baseband unit (BBU) and a remote radio head (RRH) in a mobile fronthaul (MFH) network. The controller to initialize a pseudorandom seeding in the BBU and RRH and to cause the BBU and RRH to generate a pair of matching pseudorandom bit sequences (PRBS) to enable the BBU and RRH to synchronize communications therebetween; to select a wavelength and to select a route, through the MFH network, to enable the BBU and RRH to communicate using the selected wavelength and route; to select an error correction code and a modulation format for communications between the BBU and RRH; to encode one or more parameters of a physical layer in the MFH network into the PRBS; and to monitor a data stream between the BBU and RRH to determine if a bit error rate has changed for each frame of the data stream.

A controller to communications between a baseband unit (BBU) and a remote radio head (RRH) in a mobile fronthaul (MFH) network. The controller to initialize a pseudorandom seeding in the BBU and RRH and to cause the BBU and RRH to generate a pair of matching pseudorandom bit sequences (PRBS) to enable the BBU and RRH to synchronize communications therebetween; to select a wavelength and to select a route, through the MFH network, to enable the BBU and RRH to communicate using the selected wavelength and route; to select an error correction code and a modulation format for communications between the BBU and RRH; to encode one or more parameters of a physical layer in the MFH network into the PRBS; and to monitor a data stream between the BBU and RRH to determine if a bit error rate has changed for each frame of the data stream.

An optical device includes a substrate, a dielectric substance laminated on the substrate, an optical waveguide surrounded by the dielectric substance, a heater electrode that is disposed above the optical waveguide and that is surrounded by the dielectric substance, and a trench. The trench includes a plurality of split trenches each of which is formed in a hollow segmented shape in the dielectric substance and in which the split trenches are disposed in parallel with the heater electrode. The split trenches are disposed in parallel with the heater electrode such that an area of the dielectric substance located between an end of each of the split trenches and a side surface of the heater electrode is gradually expanded.