An optomechanical device for modulating an optical signal for reducing thermal noise and tracking mechanical resonance of a proof mass assembly comprises a circuit configured to receive, from a light-emitting device, the optical signal and modulate the optical signal to remove thermal noise and to drive a mechanical response frequency to the mechanical resonance of the proof mass assembly using a cooling feedback signal and a mechanical resonance feedback signal. The circuit is further configured to generate, using the modulated optical signal, the cooling feedback signal to correspond to a thermal noise signal of the modulated optical signal with a total loop gain of zero and a phase difference of 180 degrees and generate, using the modulated optical signal, the mechanical resonance feedback signal to drive the mechanical response frequency of the modulated optical signal to the mechanical resonance.

An example node includes a receiver, a switch circuit, and a transmitter. The receiver is configured to receive a first modulated optical signal including a first plurality of optical subcarriers, and supply a plurality of data streams based on the first plurality of optical subcarriers. Each of the data streams is associated with a corresponding one of the plurality of optical subcarriers. The switch circuit is configured to receive the data streams, and supply the data streams to a plurality of switch outputs. The transmitter is configured to receive the data streams, and supply a second modulated optical signal based on the data streams. The second modulated optical signal carries a second plurality of optical subcarriers. Each of the second plurality of optical subcarriers is associated with a corresponding one of the data streams.

In an example method, network traffic transmitted between a plurality of network nodes via a communications network is monitored. Subsets of the network traffic are ranked according to one or more ranking criteria. A mesh network is deployed between the plurality of network nodes based on the ranking of the subsets of the network traffic. The mesh network includes a plurality of network links, where each network link communicatively couples a respective network node from among the plurality of network nodes to another respective network node from among the plurality of network nodes.

An example system includes a network switch and a plurality of server computers communicatively coupled to the first network switch. The network switch includes a first transceiver configured to transmit data according to a first maximum throughput, and each server computer includes a respective second transceiver configured to transmit data according to a second maximum throughput that is less than the first maximum throughput. The network switch is configured to transmit, using the first transceiver according to the first maximum throughput, first data including a plurality of optical subcarriers to each of the server computers. Each of the server computers is configured to receive, using a respective one of the second transceivers, the first data from the network switch, and extract, from the first data, a respective portion of the first data addressed to the server computer.

An example system includes a plurality of network nodes, each including one or more respective first transceivers configured to transmit data according to a first maximum throughput, and one or more respective second transceivers configured to transmit data according to a second maximum throughput that is less than the first maximum throughput. A first network node is configured to transmit, using a respective one of the first transceivers, first data including a plurality of optical subcarriers to two or more second network nodes according to the first maximum throughput, each optical subcarrier being associated with a different one of the two more other network nodes. The two or more second network nodes are configured to receive, using respective ones of the second transceivers, the first data from the first network node.

An example system includes a first network node, a second network node, and a third network node. The first network node is configured to generate a first optical subcarrier representing first data, and transmit the first optical subcarrier to the second network node. The second network node is configured to receive the first optical subcarrier from the first network node, generate a second optical subcarrier representing the first data, where the second optical subcarrier is different from the first optical subcarrier, and transmit the second optical subcarrier to the third network node.

An apparatus includes a first reconfigurable optical add/drop multiplexer (ROADM) to receive a first optical signal and a second ROADM to receive a second optical signal. The apparatus also includes a reconfigurable optical switch that includes a first switch, switchable between a first state and a second state, to transmit the first optical signal at the first state and block the first optical signal at the second state. The reconfigurable optical switch also includes a second switch, switchable between the first state and the second state, to transmit the second optical signal at the first state and block the second optical signal at the second state. The reconfigurable optical switch also includes an output port to transmit an output signal that is a sum of possible optical signals transmitted through the first switch and the second switch.

An optical communication system configured with a station-side apparatus and a plurality of subscriber-side apparatuses in a bus network topology includes an optical amplification unit installed on a station side, and a drop unit configured to branch an optical signal and excitation light, wherein the optical amplification unit includes an amplifier configured to amplify a downlink signal, and an excitation light output unit configured to output the excitation light for amplifying an uplink signal to a communication path, and the drop unit changes a branching ratio in accordance with a wavelength of the optical signal so that a transmission loss of the excitation light with respect to a trunk fiber is reduced.

A frequency stabilizer includes: a delay line interferometer that receives an optical signal corresponding to one frequency mode of a pulsed laser, divides and transmits the received optical signal to a reference arm and a delay arm including an optical fiber delay line, and then outputs an interference signal between signals passing through the reference arm and the delay arm; a photoelectric converter that converts the interference signal into an electrical signal; a mixer that generates a baseband signal of the electrical signal by mixing a carrier frequency signal; and a feedback controller that transmits a control signal generated based on the baseband signal to the pulsed laser. The optical signal passing through the delay arm is weighted with a delay time caused by the optical fiber delay line compared to the optical signal passing through the reference arm, and the optical signal passing through the delay arm is frequency shifted to a carrier frequency of an oscillator. A carrier-envelope offset frequency of the pulsed laser is stabilized by an offset frequency stabilizer.

A branching unit branches a first wavelength-multiplexed optical signal input through a first transmission line, the first wavelength-multiplexed optical signal including first and second optical signals, A wavelength selection unit receives the branched first wavelength-multiplexed optical signal branched by the branching unit, receives a second wavelength-multiplexed optical signal including a third optical signal in the same band as that of the first optical signal and a fourth optical signal in the same band as that of the second optical signal through a second transmission line, outputs a third wavelength-multiplexed optical signal including the first and fourth optical signals optical to a third transmission line and output the third optical signal. A multiplexing unit outputs a fourth wavelength-multiplexed optical signal in which the branched first wavelength-multiplexed optical signal branched by the branching unit and the third optical signal output from the wavelength selection unit are multiplexed to a fourth transmission line.