Optical Communication Research Articles

Controllable switching based on vortex–antivortex pairs in exciton–polariton condensates

Abstract Vortex–antivortex pairs hold significant prospect for applications in high-capacity optical communications, multiparticle manipulations, and data processing systems. In this work, based on vortex–antivortex pairs, we explore a straightforward method to produce a 1–4 optical switch in a polariton condensate with a C-shaped potential. The switch, seeded by a degenerate state containing two vortex–antivortex pairs, can selectively target four objective states: two orthogonal states with a single vortex–antivortex pair and two concentric vortices with opposite circulations. All these topological states are stable states with the application of a single incoherent pump, while the switch is activated by an additional coherent control pulse.

Dynamical structures of optical solitons for highly dispersive perturbed NLSE with $$\beta $$-fractional derivatives and a sextic power-law refractive index using a novel approach

Dynamical structures of optical solitons for highly dispersive perturbed NLSE with $$\beta $$-fractional derivatives and a sextic power-law refractive index using a novel approach

High performance measurement of preamplifier circuits based bipolar/field effect transistors for the optimum photodiode receivers performance in optical communication system

Abstract This paper indicated the high speed preamplifier circuits based bipolar/field effect transistors for the optimum photodiode receiver’s performance in optical communication system. The total photodiode bandwidth is studied against photodiode capacitance and input photodiode resistance. The total photodiode bandwidth is demonstrated against photodiode capacitance and ambient temperature variations. The total photodiode spectral/thermal noise density is clarified versus the photodiode based bipolar/FET transistor and ambient temperature variations. The total photodiode transconductance, optimum photodiode gain and the optimum photodiode signal per noise ratio are analyzed and clarified against the photodiode based bipolar/FET transistor and ambient temperature variations at various input photodiode resistance. Bit error rate at receiver is demonstrated versus the photodiode based bipolar/FET transistor and input photodiode resistance variations at various ambient temperature.

Efficiently catching entangled microwave photons from a quantum transducer with shaped optical pumps

A quantum transducer, when working as a microwave and optical entanglement generator, provides a practical way to coherently connect optical communication channels and microwave quantum processors. Recent experiments on a quantum transducer verifying entanglement between the microwave and optical photons show the promise of approaching that goal. While flying optical photons can be efficiently controlled or detected, the microwave photon needs to be stored in a cavity or converted to the excitation of a superconducting qubit for further quantum operations. However, it remains challenging to efficiently capture or detect a single microwave photon with an arbitrary time profile. This work focuses on this challenge in the setting of an entanglement-based quantum transducer and proposes a solution by shaping the optical pump pulse. By Schmidt decomposing the output entangled state, we show that the microwave-optical photon pair takes a specific temporal profile that is controlled by the optical pump. The microwave photon from the transducer can be nearly perfectly absorbed by a receiving cavity with tunable coupling and is ready to be converted to the excitation of superconducting qubits, enabling further quantum operations. Published by the American Physical Society 2024

Advanced decision scheme to mitigate phase impairments in coherent optical transmission systems

An advanced decision scheme is proposed to mitigate phase impairments in coherent optical communication systems. First, the centers of received signals affected by nonlinear impairment are calculated using tangential and radial hierarchical clustering. Then signal decisions with phase noise and nonlinear impairment tolerance are achieved through phase subsequence clustering, resulting in the improvement of transmission performance and the reduction of the computational complexity. The proposed scheme was simulated and experimentally verified in a 216 Gbit/s uniform and probabilistic-shaped (PS) polarization division multiplexing (PDM) 64-quadrature amplitude modulation (64-QAM) coherent optical communication system. The results indicate that the proposed scheme achieves a power budget increase of 0.1 dB in the uniform 64-QAM system and 1.7 dB in the PS 64-QAM system, respectively, compared to the cascaded schemes of 2-stage blind phase search and K-means. Furthermore, the proposed scheme reduces the computational complexity by 86.5% and 93.9%, respectively.

Multiplane Optimizing Phase Holograms Using Advanced Machine Learning Algorithms and GPU Acceleration

Phase holography is a critical optical imaging and information processing technique with applications ranging from microscopy to optical communications. However, optimizing phase hologram generation remains a significant challenge due to the non-convex nature of the optimization problem. This paper presents a novel multiplane optimization approach for phase hologram generation to minimize the reconstruction error across multiple focal planes. We significantly improve holographic reconstruction quality by integrating advanced machine learning algorithms like RMSprop and Adam with GPU acceleration. The proposed method utilizes TensorFlow to implement custom propagation layers, optimizing the phase hologram to reduce errors at strategically selected distances.

Anisotropic Coupling‐Based 2D Material Dember Polarized Photodetectors

AbstractPolarization photodetectors (PPDs) based on 2D materials hold great promise for ultracompact polarimeters due to their ability to directly detect polarization states. However, the existing PPDs based on 2D materials tend to focus on a single metric, making it challenging to obtain both a large polarization ratio (PR) and high responsivity (R). Here, black phosphorus (BP) PPDs are proposed under a nanowire configuration that enables large PR and high R simultaneously. Benefitting from the anisotropic coupling between the BP crystal and the nanowire geometry, specific light‐field distributions are formed under orthogonally polarized light incidences, through selectively exciting the localized surface plasmon and leaky‐mode resonances. A large carrier concentration gradient inherent to this structure is formed to induce a high response contrast and a large Dember current, enabling an ultrahigh PR ≈ 118.4, R ≈ 802.42 A W−1, and ultrashort response time ≈ 636 ps. Finally, a key‐free optical encryption communication system is constructed, demonstrating one of its promising applications.

Demonstration of a three-active-section DFB laser with photon-photon resonance and detuned loading effects to obtain enhanced bandwidth and maintained high output power

Enhancement of the modulation bandwidth of the directly modulated semiconductor laser has attracted tremendous attention for applications in optical fiber communication and optical interconnects. However, modulation bandwidth is enhanced by some special technology such as integrating the active region or passive region regularly, which lead to low power and complex fabrication. Here we design and demonstrate a monolithic integrated three-active-section distributed feedback (TAS-DFB) laser with enhanced bandwidth theoretically and experimentally. The laser includes three sections: the DFB section, feedback section and active phase section. The three sections share the same multiple quantum-well structure. To enhance the modulation bandwidth beyond the intrinsic modulation bandwidth, both photon-photon resonance (PPR) and detuned loading (DL) effects are utilized to achieve over 55 GHz. The active phase section shows promise in achieving high bandwidth with PPR and relatively high output power of ∼ 10 mW at 25 °C under continuous-wave (CW) operation simultaneously. The fabrication process of the TAS-DFB laser is simplified due to the conventional and identical active layer structure.

Design and numerical analysis of a modified core hexa–deca photonic crystal fiber for highly negative dispersion and birefringence control in optical communication bands

The paper presents a thorough investigation into the design of a Modified Core Hexa–Deca Photonic Crystal Fiber (MHD-PCF) with adjustable features to regulate dispersion and birefringence. At the target wavelength of 1550 nm, the suggested MHD-PCF exhibits extraordinary optical properties, including an ultra-high negative dispersion coefficient of − 7755 ps/(nm km) and significant birefringence of 1.905 × 10−2. The analysis entails regular changes in lattice constants and center air hole parameters, which provide insights into optical property trends. The MHD-PCF regularly exceeds existing benchmarks across a wide range of parameter adjustments. Notably, this fiber has strong nonlinearity (59.12 W−1 km−1) and low confinement loss (2.896 × 10−3 dB/cm), as well as an enhanced numerical aperture (0.5144), demonstrating its potential for efficient light coupling and supercontinuum production. These results put the Modified Core Hexa–Deca Photonic Crystal Fiber at the forefront of contemporary communication systems, and its optical enhancements and flexible features present exciting opportunities for novel Terahertz technology breakthroughs, especially in the areas of communication systems and sensing applications.

A new investigation of the extended Sakovich equation for abundant soliton solution in industrial engineering via two efficient techniques

Abstract Soliton solutions play a crucial role in modeling stable phenomena across optical communications, fluid dynamics, and plasma physics, owing to their stability and persistence in solving nonlinear equations. This study centers on the extended Sakovich equation, emphasizing the importance of soliton solutions in predicting and controlling localized wave behaviors, which advances nonlinear dynamics and its various applications due to its integrable properties and flexible soliton characteristics. This equation is applicable across diverse fields such as fluid dynamics, nonlinear optics, and plasma physics, where it effectively models nonlinear wave phenomena, including solitons and shock waves. Additionally, it provides crucial insights into wave propagation in biological systems and acoustics, making it a valuable tool for analyzing complex wave dynamics. Additionally, we investigate bifurcation and modulation instability within this equation, employing the improved Sardar subequation method and the ℛ ′ ℛ , 1 ℛ \left(\phantom{\rule[-0.75em]{}{0ex}},\frac{{ {\mathcal R} }^{^{\prime} }}{ {\mathcal R} },\frac{1}{ {\mathcal R} }\right) method to derive solitary wave solutions. These methods yield a diverse range of waveforms – hyperbolic, trigonometric, and rational functions – validated rigorously using Mathematica software for accuracy. Graphical representations vividly display various soliton patterns, such as singular, multi-singular, periodic singular, kink, anti-kink, bell-shaped, Kuznetsov–Ma Breather, and parabolic-shaped, highlighting their effectiveness in revealing innovative solutions. Furthermore, a comparative analysis verified the novelty of our derived soliton solutions. This research significantly contributes to advancing soliton solutions for the Sakovich equation, promising diverse applications across scientific disciplines.

Hong-Ou-Mandel interference with a coexisting clock using transceivers for synchronization over deployed fiber

Interference between independently generated photons is a key step towards distributing entanglement over long distances, but it requires synchronization between the distantly-located photon sources. Synchronizing the clocks of such photon sources using coexisting two-way classical optical communications over the same fiber that transports the quantum photonic signals is a promising approach for achieving photon–photon interference over long distances, enabling entanglement distribution for quantum networking using the deployed fiber infrastructure. Here, we demonstrate photon–photon interference by observing the Hong-Ou-Mandel dip between two distantly-located sources: a weak coherent-state source obtained by attenuating the output of a laser and a heralded single-photon source. We achieve a maximum dip visibility of 0.58±0.04 when the two sources are connected via 4.3 km of deployed fiber. Dip visibilities >0.5 are nonclassical and a first step towards achieving teleportation over the deployed fiber infrastructure. In our experiment, the classical optical communication is achieved with −21 dBm of optical signal launch power, which is used to synchronize the clocks in the two independent, distantly-located photon sources. The impact of spontaneous Raman scattering from the classical optical signals is mitigated by appropriate choice of the quantum- and classical-channel wavelengths. All equipment used in our experiment (the photon sources and the synchronization setup) is commercially available. Finally, our experiment represents a scalable approach to enabling practical quantum networking with commercial equipment and coexistence with classical communications in optical fiber.

Characteristics of metallic coated ultra-short semiconductor Fabry-Pérot lasers

Fabry-Pérot (F–P) lasers have attracted significant attention due to their extensive applications in optical communication and precision measurement fields. However, traditional F–P lasers are relatively large in size and face challenges in directly achieving single-mode lasing, which limits their applications. In this study, we employ a metallic coating layer to significantly enhance the light confinement of the F–P cavity, thereby substantially reducing the cavity length of the F–P laser. We have experimentally developed an F–P laser with a cavity length of approximately 6.8 μm, successfully achieving single-mode lasing at room temperature. The lasing mode exhibits an ultra-narrow linewidth of 0.06 nm and a relative high side-mode suppression ratio exceeding 30 dB, along with good linear polarization. Additionally, we propose a type of on-chip integrated laser based on metallic-coated F–P cavities, characterized by high coupling efficiency and large fabrication tolerances. Simulation results indicate that the coupling efficiency for double-ended and single-ended output waveguides reaches 79% and 55%, respectively. The metallic-coated ultra-short F–P lasers have great potential for applications in on-chip optical interconnects and photonic integrated chip systems.

Integrated lithium niobate Vernier micro-ring filter with wide and fast tuning capabilities

Tunable optical micro-ring filters play significant roles in optical communications, microwave photonics, and photonic neural networks. Typical micro-ring filters are based on either a thermo-optic (TO) effect with microsecond timescales or an electro-optic (EO) effect with a limited tuning range. Here, we report a continuously tunable lithium niobate on insulator (LNOI) Vernier cascaded micro-ring filter with wire-bonded packaging integrated with both TO and EO tuning electrodes, featuring a 40-nm free spectral range (FSR), 2.3 GHz EO bandwidth, and a high sidelobe suppression ratio of 21.7 dB, simultaneously. Our high-performance optical micro-ring filter could become an important element in future LNOI photonic circuits with applications in high-capacity wavelength-division multiplexing (WDM) systems, broadband microwave photonics, fast-tunable external-cavity lasers, and high-speed photonic neural networks.

Observation of orbital angular momentum from an ultrathin topological insulator metasurface.

Orbital angular momentum (OAM) existing in the vortex light beam with isolated singularities and spiral phase distribution presents significant applications in optical communications and light-field manipulation. The generation of OAM based on plasmonic metasurfaces is generally limited by the large optical loss and weak tunability of metal materials. Three-dimensional (3D) topological insulators (TIs) with insulating bulk states and topologically protected surface states allow the excitation of surface plasmons with low loss in the high-frequency region. Herein, we designed and fabricated an ultrathin Sb2Te3 TI plasmonic metasurface using the magnetron sputtering deposition and focused ion beam lithography. The results show that the 18 nm thick TI metasurface can efficiently generate surface plasmon resonances (SPRs) in the visible spectrum, which can effectively modulate the spatial phase of incident light for the generation of OAM. We find that the OAM conversion efficiency of the TI-based metasurface is remarkable compared with that of the gold-based metasurface. The experimental results obtained by a self-built OAM testing system demonstrate that the ultrathin TI metasurface can generate a distinct vortex beam with a first-order topological charge. This work will provide a new approach for generating OAM in ultrathin structures and exploring the applications of TIs in light-field manipulation.

Retraction Note: A hybrid QL ANN model designed to improve the Quality of Transmission of optical communication network

Retraction Note: A hybrid QL ANN model designed to improve the Quality of Transmission of optical communication network

Optical soliton noninteraction transmission in optical communication systems

The building of the national communication infrastructure and growing demand for data traffic both depend heavily on the advancement of optical soliton communication technology. In particular, by studying the interaction of optical solitons, some methods of controlling optical solitons can be explored to design more stable and efficient optical communication systems. In this paper, the interactions between optical solitons are studied based on the theory of generalized Schrödinger–Hirota equation. By studying the amplitude ratio, spacing and phase difference of the optical solitons, the interactions between the optical solitons occurring in the optical fiber transmission process are attenuated. The noninteraction transmission of optical solitons are realized with small spacing between them. The conclusions of this paper are not only of great significance for the in-depth understanding of the nature of optical soliton interactions, but also of great practical value for promoting the application of optical solitons in optical communications and other fields.

Enhanced Coplanarity and Giant Birefringence in Hydroxypyridinium Nitrate via Hydrogen Bonding between Planar Donors and Planar Acceptors

AbstractBirefringent crystals, which possess optical anisotropy, are important optical components. However, designing and synthesizing birefringent crystals faces the challenge of achieving anisotropic structures, especially coplanar geometries. Herein, we achieve a significant birefringence in an ionic compound (C5H6ON)+(NO3)−, (4‐hydroxypyridinium nitrate, 4HPN) by hydrogen bonding between planar donors and planar acceptors. We demonstrate that the interactions between the planar hydrogen bond donor ((C5H6ON)+) and planar hydrogen bond acceptor ((NO3)−) ensure the coplanarity during the crystal packing, generating the desired giant optical anisotropy. On two manually cut crystal chips, we observe a =0.494 ( =0.593), which is the largest among nitrates, or hydroxypyridinium derivatives. This value already surpasses those of the benchmark crystals, e.g., YVO4 and CaCO3, commonly used in the UV to visible and near IR spectral range. 4HPN also exhibits a strong second harmonic generation response (9.55×KDP). This strategy offers a promising avenue for the design and development of birefringent crystals with potential applications in optical communication, sensing and signal processing devices.

Retraction Note: Massive MIMO based beamforming by optical multi-hop communication with energy efficiency for smart grid IoT 5G application

Retraction Note: Massive MIMO based beamforming by optical multi-hop communication with energy efficiency for smart grid IoT 5G application

Enhanced ultrafast nonlinear optical response in Bi-doped ZnO glass-ceramics

Incorporating plasmonic nanocrystals (NCs) into solid-state electronics is an important step toward realizing nanophotonic devices. However, only a few noble metal-based systems can directly precipitate plasmonic NCs in a solid transparent medium. In contrast, plasmonic metal oxide NCs can exhibit a plasmonic response at infrared energies that noble metal-based systems cannot reach due to their high carrier concentration. Here we demonstrate the precipitation of bismuth-doped ZnO (BZO) NCs in an aluminosilicate glass matrix, demonstrating a robust near-infrared (NIR)-localized surface plasmon resonance. Benefited from the strong resonant absorption by the plasmonic BZO NCs, these glass ceramics (GCs) exhibit enhanced ultrafast nonlinear optical (NLO) response across the NIR optical communication bands, which might be promising for applications such as optical limiting, optical switching, optical modulation, and NIR-nanophotonic devices.

Retraction Note: Radar optical communication for analysing aerial targets with frequency bandwidth and clutter suppression by boundary element mmwave signal model

Retraction Note: Radar optical communication for analysing aerial targets with frequency bandwidth and clutter suppression by boundary element mmwave signal model