Current Issue : April-June Volume : 2026 Issue Number : 2 Articles : 5 Articles
Neuromorphic devices based on carrier relaxation have demonstrated significant potential in simplifying the integration of sensory-computing neural network chips. However, typical relaxation designs rely on defect sustained-release mechanisms and interaction with bulk channel carriers, which compromise sensing performance and hinder the effective coordination of gains between computing and sensing functions. Herein, the limitation is addressed by confining the interaction between defects and carriers to a 2D interface involving Tellurium (Te) and the Hafnium Dioxide (HfO2)/hexagonal Boron Nitride (h-BN). This approach enables high-fidelity perception and computation of optical communication timing sequences through precise defect modulation to allocate modal weights. The device exhibits competitive photo-electric conversion performance for communication digital signals under zero gate bias. More notably, under applied gate bias, the device can function as an optical synapse with a rise time 𝝉rise of 1.04 ms, the synaptic response processes can be directly utilized as a sequence detector rather than merely contributing to the final conductance. By simultaneously performing sensing and computing functionalities within a single device, high-precision timing recovery is achieved for optical communication using a spiking neural network (SNN) algorithm. This work presents a pioneering verification and offers a potential high-performance architecture reference for compact clock-free optical communication modules....
This article covers the rarely focused-on topic of optimizing unmanned aerial vehicle (UAV) flight paths around telecommunication masts. Due to the large variety of structures, along with additional obstacles such as stiffening struts, nearby buildings, and tall vegetation, collecting object data is a complex and demanding problem. One of the main applications of small UAVs is the ability to generate a point cloud of various objects. These are generated using pictures taken by the UAV and information about its position, which are then subjected to special analysis. This article examines the development of an optimal method for conducting flights around telecommunication masts. Many additional difficulties characterize this type of object. Among them, we can include lashings, communication interference caused by wave propagation through antennas, and the high diversity of objects. Finding an optimal, general methodology for performing such flights, taking into account all the difficulties and requirements for the later-generated point cloud, becomes a very complex and complicated problem. In this work, the problems of performing optimal flights around telecommunication masts are described. Then, solutions for taking pictures and different flight paths are considered. An example application for creating flight trajectories around such masts, written in the MATLAB (ver. R2022b) environment, is also presented. Finally, the results and conclusions obtained are described....
The absence of natural sources of circularly polarized light has created a critical demand for high-performance polarization converters in emerging technologies such as quantum information processing, biomedical diagnostics, and advanced magneto-optical recording systems. Despite significant efforts, linear-to-circular polarization converters that combine high efficiency with tunability remain scarce. In this paper, we present a multifunctional and tunable device with 99.9% efficiency for converting linear to circular polarization in the telecom wavelength range. It can also function as a phase-only compensator with a controllable phase range of 1.93π while maintaining a reflectance above 99%. The angular sensitivity analysis indicates that the device can tolerate incidence angles ranging from 8 to 10.4 degrees. This high-efficiency polarization conversion device offers significant advantages in integrated optics due to its multifunctionality and tunability and has promising applications in optical phased-array radars and quantum communication....
We report on optimizing the spectral purity of heralded single photons in the telecom O-band, where single photons can be propagated with low loss and low dispersion in a standard telecom optical fiber. We numerically searched for various group-velocity-matching conditions and corresponding optimal poling structures of a potassium titanyl phosphate crystal for spontaneous parametric downconversion. Our poling optimization results using phase-matching coherence-length and subcoherence- length modulation schemes show > 99.4% spectral purity with pump wavelengths ranging from 603.8 to 887.3 nm. Some optimized configurations are feasible with off-the-shelf lasers and single-photon detectors. Moreover, by investigating noise photon spectra for different poling optimization methods, we show that, in practice, appropriate, gentle spectral filtering helps achieve high purity. This study will pave the way for developing practical quantum sources for quantum information applications at the telecom O-band....
This work presents the design and experimental validation of a 2 × 2 MIMO communication system assisted by a directly modulated analog radio-over-fiber (A-RoF) fronthaul, targeting low-complexity connectivity solutions for underserved/remote regions. The study details the complete end-to-end architecture, including a wireless access segment to complement the 20-km optical fronthaul link. The system is implemented on an software defined radio (SDR) platform using GNU Radio 3.7.11, running on Ubuntu 18.04 with kernel 4.15.0-213-generic. It also employs adaptive modulation driven by real-time signal-to-noise ratio (SNR) estimation to keep bit error rate (BER) close to zero while maximizing throughput. Performance is characterized over 20 km of single-mode fiber (SMF) using coarse wavelength division multiplexing (WDM) and assessed through root mean square error vector magnitude (EVMRMS), throughput, and spectral integrity. The results identify an optimum radio-frequency drive region around −16 dBm enabling high-order modulation (e.g., 256-QAM), whereas RF input powers above approximately −10 dBm increase EVMRMS due to nonlinearity in the RF front-end/low-noise amplifier (LNA) and direct modulation stage, forcing the adaptive scheme to reduce modulation order and throughput. Over the optical-power sweep, when the incident optical power exceeds approximately −8 dBm, the system reaches ∼130 Mbps (24-MHz channel) with EVMRMS approaching ∼1%, highlighting the need for careful joint tuning of RF drive, optical launch power, and wavelength allocation across transceivers. Finally, the integrated access link employs diplexers for transmitter/receiver separation in a 2 × 2 configuration with 2.8 m antenna separation and low channel correlation, demonstrating a 10 m proof-of-concept range and enabling end-to-end spectrum/EVM/throughput observations across the full communication chain....
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