A network or system in which a hub or primary node may communicate with a plurality of leaf or secondary nodes. The hub node may operate or have a capacity greater than that of the leaf nodes. Accordingly, relatively inexpensive leaf nodes may be deployed to receive data carrying optical signals from, and supply data carrying optical signals to, the hub node. One or more connections may couple each leaf node to the hub node, whereby each connection may include one or more spans or segments of optical fibers, optical amplifiers, optical splitters/combiners, and optical add/drop multiplexer, for example. Optical subcarriers may be transmitted over such connections, each carrying a data stream. The subcarriers may be generated by a combination of a laser and a modulator, such that multiple lasers and modulators are not required, and costs may be reduced. As the bandwidth or capacity requirements of the leaf nodes change, the number of subcarriers, and thus the amount of data provided to each node, may be changed accordingly. Each subcarrier within a dedicated group of subcarriers may carry OAM or control channel information to a corresponding leaf node, and such information may be used by the leaf node to configure the leaf node to have a desired bandwidth or capacity.

An optical communications system includes a laser transmitter to generate an optical signal and a first optical fiber network coupled to transmit the optical signal from the laser transmitter system. A first latchable, asymmetric coupler is disposed along the first optical fiber network to receive the optical signal, and has a first tap output that receives a selected and alterable first fraction of the optical signal. A second latchable, asymmetric coupler is disposed along the first optical fiber network to receive the optical signal from the first latchable asymmetric coupler and has a second tap output that receives a selected and alterable second fraction of the optical signal incident at the second latchable. In certain embodiments the first and second couplers are capable of operating at any of at least three tapping fractions.

Embodiments are disclosed for a quantum key distribution enabled intra-datacenter network. An example system includes a first vertical cavity surface emitting laser (VCSEL), a second VCSEL and a network interface controller. The first VCSEL is configured to emit a first optical signal associated with data. The second VCSEL is configured to emit a second optical signal associated with quantum key distribution (QKD). Furthermore, the network interface controller is configured to manage transmission of the first optical signal associated with the first VCSEL and the second optical signal associated with the second VCSEL via an optical communication channel coupled to a network interface module.

A system for generating and receiving a polarization multiplexed single sideband signal is provided, which includes a light wave generating unit connected with a signal modulating unit and configured to generate a light wave; a driving signal generating unit connected with the signal modulating unit and configured to generate a driving signal; the signal modulating unit configured to split the light wave into two orthogonal polarized light waves, and modulate the driving signal on the polarized light waves to obtain a polarization multiplexed upper sideband optical signal and a polarization multiplexed lower sideband optical signal which are coupled to output a mixed signal, the mixed signal is transmitted to a separating and converting unit to obtain electrical millimeter wave signals; the electrical millimeter wave signals are transmitted through an MIMO wireless link to a signal sampling and processing unit to be converted into digital signals for digital signal processing.

A transceiver comprises a transmitter including a light source, a modulator coupled to the light source, a driver that drives the modulator according to a set of driving conditions to cause the modulator to output optical signals based on light from the light source, and an output that passes first portions of the optical signals output by the modulator. The transceiver further comprises a first detector that detects second portions of the optical signals output from the modulator, and a receiver including a second detector that detects optical signals from an external transmitter.

An optical emitting device includes a base, a thermoelectric cooler, an optical communication assembly and a circuit board. The base includes a main body and a stem connected with each other. The stem extends from a basal surface of the main body, and a normal of a supporting surface of the stem is non-parallel to a normal of the basal surface of the main body. The thermoelectric cooler is disposed on the supporting surface of the stem. The optical communication assembly is disposed on the thermoelectric cooler, and the thermoelectric cooler is between the optical communication assembly and the stem. The circuit board is disposed on the base and passes through the main body and electrically connected with the optical communication assembly.

A coherent optical transmitter is in operable communication with an optical fiber an includes a plurality of analog-to-digital converters (ADCs) configured to (i) receive a plurality of radio frequency analog input signals, respectively, and (ii) convert the received plurality of RF analog input signals into a plurality of respective digital data streams. The transmitter further includes a source laser configured to output at least two orthogonal polarization component signals, and at least two polarization modulators configured to modulate (i) an in-phase portion output from a first ADC, (ii) an in-quadrature portion output from a second ADC, and (iii) one polarization component signal of the at least two orthogonal polarization component signals. The transmitter further includes a polarization beam combiner configured to (i) multiplex the respective outputs of the at least two polarization modulators, and (ii) transmit the multiplexed output from the polarization beam combiner to the optical fiber.

An underwater optical communication system (100) is provided with a first optical communication device (1) that includes a first filter (12), a second optical communication device (2) that includes a second filter (22) and performs bi-directional optical communication with the first optical communication device. The first filter is configured to selectively transmit light of a predetermined wavelength band including a second wavelength (41) but not including a first wavelength (40). The second filter is configured to selectively transmit light of a predetermined wavelength band including the first wavelength but not including the second wavelength.

A radio communication system for duplex communication comprising an optical carrier generator for generating optical carrier signals, a local oscillator (LO) for generating an electrical signal in a radio communication band, an information signal source, electro-optic modulators driven directly at an input electrical port by said information signal and said LO signal to modulate a portion of said optical carrier signal to form a modulated portion being an optical band information signal for transmission over an optical link; and a photodetector remote from said electro-optic modulators for receiving said transmitted optical band information signal from said optical link, and directly generating an electrical signal that is up-converted for radio transmission, or down-converted to a baseband frequency.

In an EADFB laser with an integrated SOA, a new configuration in which deterioration of optical waveform quality is solved or mitigated while taking advantage of characteristics that the same layer structure can be used and the manufacturing process can be simplified is shown. In an optical transmitter of the present disclosure, a carrier density is optimized depending on a light intensity inside the SOA and an amount of carrier consumption. The SOA is electrically separated into a plurality of regions, and a current is injected into each region independently. The divided SOA region is configured so that a length of the SOA region becomes shorter as a region is farther from an incidence end of the SOA. Further, for the divided SOA, an amount of carrier consumption increases as the SOA region is farther from the incidence end, so that a current injection amount is increased.