While considerable research has been conducted on the structural principles, fabrication techniques, and photoelectric properties of high-voltage light-emitting diodes (LEDs), their performance in light communication remains underexplored. A high-voltage series-connected LED or photodetector (HVS-LED/PD) based on the gallium nitride (GaN) integrated photoelectronic chip is presented in this paper. Multi-quantum wells (MQW) diodes with identical structures are integrated onto a single chip through wafer-scale micro-fabrication techniques and connected in series to construct the HVS-LED/PD. The advantages of the HVS-LED/PD in communication are explored by testing its performance as both a light transmitter and a PD. The series connection enhances the device's 3 dB bandwidth, allowing it to increase from 1.56 MHz to a minimum of 2.16 MHz when functioning as an LED, and from 47.42 kHz to at least 85.83 kHz when operating as a PD. The results demonstrate that the light communication performance of HVS-LED/PD is better than that of a single GaN MQW diode with bandwidth and transmission quantity, which enriches the research of GaN-based high-voltage devices.

Harvesting energy from environmental sources such as solar and wind can mitigate or solve the limited-energy problem in wireless sensor networks. In this paper, we propose an energy-harvest-aware route-selection method that incorporates harvest availability properties and energy storage capacity limits into the routing decisions. The harvest-aware routing problem is formulated as a linear program with a utility-based objective function that balances the two conflicting routing objectives of maximum total and maximum minimum residual network energy. The simulation results show that doing so achieves a longer network lifetime, defined as the time-to-first-node-death in the network. Additionally, most existing energy-harvesting routing algorithms route each traffic flow independently from each other. The LP formulation allows for a joint optimization of multiple traffic flows. Better residual energy statistics are also achieved by such joint consideration compared to independent optimization of each commodity.

Split-step digital backward propagation (DBP) can be combined with coherent detection to compensate for fiber nonlinear impairments. A large number of DBP steps is usually needed for a long-haul fiber system, and this creates a heavy computational load. In a trade-off between complexity and performance, interchannel nonlinearity can be disregarded in order to simplify the DBP algorithm. The number of steps can also be reduced at the expense of performance. In periodic dispersion-managed long-haul transmission systems, optical waveform distortion is dominated by chromatic dispersion. As a result, the nonlinearity of the optical signal repeats in every dispersion period. Because of this periodic behavior, DBP of many fiber spans can be folded into one span. Using this distance-folded DBP method, the required computation for a transoceanic transmission system with full inline dispersion compensation can be reduced by up to two orders of magnitude with negligible penalty. The folded DBP method can be modified to compensate for nonlinearity in fiber links with non-zero residual dispersion per span.