Photonic Communication Research Articles

Enhancement of graphene Faraday rotation in the one-dimensional topological photonic crystals

One-dimensional topological photonic crystals (TPCs) with graphene sheet have been proposed to enhance the Faraday rotation (FR). Because of the strong localized field of the topological interface state, the enhanced FR angle with high transmittance has been confirmed. The effects of external magnetic field, unit cell number and multiple interface states of multilayers on FR angle and transmittance are studied. As a result, the FR is raised, which shows a field enhancement constraint at the interface between the TPCs with graphene. The FR angle can reach 16.2° with the high transmission (70%). By constructing multiple interface states, multiple transmission peaks and FR angles are further achieved. Our result would give a fresh idea, which could be applied in nonreciprocal photonic device or optical communication systems.

Journal of Selected Topics in Quantum Electronics on Machine Learning in Photonic Communication and Measurement Systems

Journal of Selected Topics in Quantum Electronics on Machine Learning in Photonic Communication and Measurement Systems

Dual-Phase Hybrid Metasurface for Independent Amplitude and Phase Control of Circularly Polarized Wave

Achieving independent control of the amplitude and phase of the electromagnetic (EM) wave by a thin flat device is very important in wireless and photonic communications. However, most of the reported metasurfaces, so far, have realized only the simultaneous control of the amplitude and phase of the linearly polarized EM wave. This communication presents a strategy to realize the independent and arbitrary control of the amplitude and phase responses for the circularly polarized EM wave by using a dual-phase hybrid metasurface that integrates both geometric and propagation phases. A beam deflector with a tailorable amplitude is then designed to verify the proposed strategy. As a proof of concept of its practical application, a circularly polarized reflector antenna with a high gain and an extremely low sidelobe is implemented by the proposed metasurface. Experimental results are in good accordance with the simulation ones, demonstrating that the sidelobe of the designed antenna can be reduced by 8 dB compared with a reflector antenna actualized by the phase-only metasurface. The proposed methodology and the metasurface can provide a new degree of freedom in controlling the circularly polarized waves by simultaneous phase and amplitude modulations, which may trigger many interests in EM/optical integration and complex EM-wave manipulations, as well as advanced metadevices for real-world applications.

Tutorials as a novel service for the optics and photonics community: editorial

Editor-in-Chief Kurt Busch introduces tutorials as a new article type in JOSA B.

Stable soliton propagation in a coupled (2 + 1) dimensional Ginzburg–Landau system**Project supported by the National Natural Science Foundation of China (Grant Nos. 11674036 and 11875008), Beijing Youth Top Notch Talent Support Program, China (Grant No. 2017000026833ZK08), Fund of State Key Laboratory of Information Photonics and Optical Communications (Beijing University of Posts and Telecommunications, Grant No. IPOC2019ZZ01), Fundamental Research Funds

A coupled (2 + 1)-dimensional variable coefficient Ginzburg–Landau equation is studied. By virtue of the modified Hirota bilinear method, the bright one-soliton solution of the equation is derived. Some phenomena of soliton propagation are analyzed by setting different dispersion terms. The influences of the corresponding parameters on the solitons are also discussed. The results can enrich the soliton theory, and may be helpful in the manufacture of optical devices.

MetaNet: a new paradigm for data sharing in photonics research.

Optimization methods are playing an increasingly important role in all facets of photonics engineering, from integrated photonics to free space diffractive optics. However, efforts in the photonics community to develop optimization algorithms remain uncoordinated, which has hindered proper benchmarking of design approaches and access to device designs based on optimization. We introduce MetaNet, an online database of photonic devices and design codes intended to promote coordination and collaboration within the photonics community. Using metagratings as a model system, we have uploaded over one hundred thousand device layouts to the database, as well as source code for implementations of local and global topology optimization methods. Further analyses of these large datasets allow the distribution of optimized devices to be visualized for a given optimization method. We expect that the coordinated research efforts enabled by MetaNet will expedite algorithm development for photonics design.

Enhanced photon communication through Bayesian estimation with an SNSPD array

Laser communication using photons should consider not only the transmission environment’s effects, but also the performance of the single-photon detector used and the photon number distribution. Photon communication based on the superconducting nanowire single-photon detector (SNSPD) is a new technology that addresses the current sensitivity limitations at the level of single photons in deep space communication. The communication’s bit error rate (BER) is limited by dark noise in the space environment and the photon number distribution with a traditional single-pixel SNSPD, which is unable to resolve the photon number distribution. In this work, an enhanced photon communication method was proposed based on the photon number resolving function of four-pixel array SNSPDs. A simulated picture transmission was carried out, and the error rate in this counting mode can be reduced by 2 orders of magnitude when compared with classical optical communication. However, in the communication mode using photon-enhanced counting, the four-pixel response amplitude for counting was found to restrain the communication rate, and this counting mode is extremely dependent on the incident light intensity through experiments, which limits the sensitivity and speed of the SNSPD array’s performance advantage. Therefore, a BER theoretical calculation model for laser communication was presented using the Bayesian estimation algorithm in order to analyze the selection of counting methods for information acquisition under different light intensities and to make better use of the SNSPD array’s high sensitivity and speed and thus to obtain a lower BER. The counting method and theoretical model proposed in this work refer to array SNSPDs in the deep space field.

Introduction to the Photonic Networks and Devices (NETWORKS) Special Issue

This special issue comprises extended versions of some of the top-scored papers that were presented at the OSA Photonic Networks and Devices (NETWORKS) meeting that was part of the OSA Advanced Photonics Congress held in Burlingame, California, USA, July 29–August 1, 2019. Here, we highlight relevant topics from included papers relating to photonic communication network development.

Lax pair and vector semi-rational nonautonomous rogue waves for a coupled time-dependent coefficient fourth-order nonlinear Schrödinger system in an inhomogeneous optical fiber**Project supported by the BUPT Excellent Ph.D. Students Foundation (Grant No. CX2019201), the National Natural Science Foundation of China (Grant Nos. 11772017 and 11805020), the Fund of State Key Laboratory of Information Photonics and Optical Communications (Beijing University of

Optical fibers are seen in the optical sensing and optical fiber communication. Simultaneous propagation of optical pulses in an inhomogeneous optical fiber is described by a coupled time-dependent coefficient fourth-order nonlinear Schrödinger system, which is discussed in this paper. For such a system, we work out the Lax pair, Darboux transformation, and corresponding vector semi-rational nonautonomous rogue wave solutions. When the group velocity dispersion (GVD) and fourth-order dispersion (FOD) coefficients are the constants, we exhibit the first- and second-order vector semi-rational rogue waves which are composed of the four-petalled rogue waves and eye-shaped breathers. Both the width of the rogue wave along the time axis and temporal separation between the adjacent peaks of the breather decrease with the GVD coefficient or FOD coefficient. With the GVD and FOD coefficients as the linear, cosine, and exponential functions, we respectively present the first- and second-order periodic vector semi-rational rogue waves, first- and second-order asymmetry vector semi-rational rogue waves, and interactions between the eye-shaped breathers and the composite rogue waves.

Editorial: Message from the Incoming Editor

Miguel Alonso, beginning his term as Editor-in-Chief, looks forward to continuing Optics Letters’ tradition of serving the optics and photonics community and publishing high-impact short communications.

Shrinkage of Cholesteric Liquid Crystalline Microcapsule as Omnidirectional Cavity to Suppress Optical Loss

AbstractCholesteric liquid crystalline (CLC) emulsions are the easiest 3D omnidirectional laser resonators to fabricate. To exploit the full potential of CLC emulsions as distributed Bragg reflection (DBR) mode laser resonators, monodispersed water‐in‐CLC‐in‐water double emulsions (CLC microcapsules) have higher performance scalability than simple CLC droplets. If laser dyes are concentrated at the center of CLC microcapsules, emitted light from the dye is 3D confined. When water is squeezed from the inner phase of a CLC microcapsule comprising an aqueous laser dye solution by means of osmotic pressure difference from the outer phase, the DBR lasing threshold of the CLC microcapsule is reduced. The shrinkage of the inner droplet contributes not only the simple reduction of the cavity length but also the suppression of the optical loss to reduce the lasing threshold. The reduced optical loss is beneficial to realize various devices: optical manipulation, photonic cross communications, and biochemical, light, and temperature sensing. Their flexible photonic structures are suitable for emerging and future optical devices like wearable optical devices.

Photonic Multiply-Accumulate Operations for Neural Networks

It has long been known that photonic communication can alleviate the data movement bottlenecks that plague conventional microelectronic processors. More recently, there has also been interest in its capabilities to implement low precision linear operations, such as matrix multiplications, fast and efficiently. We characterize the performance of photonic and electronic hardware underlying neural network models using multiply-accumulate operations. First, we investigate the limits of analog electronic crossbar arrays and on-chip photonic linear computing systems. Photonic processors are shown to have advantages in the limit of large processor sizes ( ${>}\text{100}\; \mu$ m), large vector sizes ( $N > 500)$ , and low noise precision ( ${\leq} 4$ bits). We discuss several proposed tunable photonic MAC systems, and provide a concrete comparison between deep learning and photonic hardware using several empirically-validated device and system models. We show significant potential improvements over digital electronics in energy ( ${>}10^2$ ), speed ( ${>}10^3$ ), and compute density ( ${>}10^2$ ).

Active formatting modulation of electromagnetically induced transparency in metamaterials

We experimentally demonstrate for the first time an active all-optical ultrafast modulation of electromagnetically induced transparency-like effect in a hybrid device of sapphire/Si/metamaterial. From numerical simulations, it can be deducted that the tuning process is attributed to the coupling between the dark mode existing in split-ring resonators and the bright mode existing in cut wire resonators. The transmission amplitude modulation is accompanied by the slow-light effect. In addition, the ultrafast formation process is measured to be as fast as 2 ps. This work should make an important contribution to novel chip-scale photonic devices and terahertz communications.

Loss compensation of surface plasmon polaritons in organic/metal nanowire heterostructures toward photonic logic processing

Surface plasmon polaritons (SPPs) are crucial for the development of next generation information and communication technologies. However, the ohmic losses inherent to all plasmonic devices seriously limit their practical application in on-chip photonic communications. Here, loss compensation of SPPs and their application in photonic logic processing was demonstrated in rationally designed organic/silver nanowire heterostructures. The heterostructures were synthesized by inserting silver nanowires (AgNWs) into crystalline organic microwires, which served as a microscale optical gain medium. These heterostructures with large organic/metal interfacial areas ensured the efficient energy transfer from excitons to SPPs. Gain for subwavelength SPPs in the heterostructure was achieved through stimulated emission of strongly confined SPPs. Furthermore, cascade gain was performed to realize basic nanoscale photonic devices, such as Boolean logic units. The results would pave an alternative avenue to incorporating SPP-enhanced devices into hybrid photonic circuitry.

Bilinear Forms and Dark-Dark Solitons for the Coupled Cubic-Quintic Nonlinear Schrödinger Equations with Variable Coefficients in a Twin-Core Optical Fiber or Non-Kerr Medium**Supported by the National Natural Science Foundation of China under Grant Nos. 11772017, 11805020, 11272023 and 11471050, the Fund of State Key Laboratory of Information Photonics and Optical Communications (Beijing University of Posts and Telecommunications), China (IPOC: 2017ZZ05),

Twin-core optical fibers are applied in such fields as the optical sensing and optical communication, and propagation of the pulses, Gauss beams and laser beams in the non-Kerr media is reported. Studied in this paper are the coupled cubic-quintic nonlinear Schrödinger equations with variable coefficients, which describe the effects of quintic nonlinearity for the ultrashort optical pulse propagation in a twin-core optical fiber or non-Kerr medium. Based on the integrable conditions, bilinear forms are derived, and dark-dark soliton solutions can be constructed in terms of the Gramian via the Kadomtsev-Petviashvili hierarchy reduction. Propagation and interaction of the dark-dark solitons are presented and discussed through the graphic analysis. With different values of the delayed nonlinear response effect b(z), where z represents direction of the propagation, the linear- and parabolic-shaped one dark-dark soltions can be derived. Interactions between the parabolic- and periodic-shaped two dark-dark solitons are presented with b(z) as the linear and periodic functions, respectively. Directions of velocities of the two dark-dark solitons vary with z and the amplitudes of the solitons remain unchanged can be observed. Interactions between the two dark-dark solitons of different types are displayed, and we observe that the velocity of one soliton is zero and direction of the velocity of the other soliton vary with z. We find that those interactions are elastic.

Directive surface wave on nanoplasmonic film: the roles of photonic spin-Hall effect and optical interactions

Interaction of the spin and orbital angular momentum of light, occurring in the photonic spin Hall effect (PSHE), leads to the separation of photons with opposite spins (two different forms of circularly polarized wave) toward opposite directions perpendicular to the pump light-beam path. As photons with two opposite spins illuminate a nanoparticle (NP) near a metal–dielectric interface (MDI), the associated evanescent fields excite spin-dependent directional surface plasmon polaritons (SPPs) with transverse spins. We show that a circularly polarized incident optical beam, which contains only one spin state, causes the directional scattering of SPPs on the nanoplasmonic-film surface, following the PSHE. Here, Green’s tensor approach in conjunction with the mode-matching technique are developed and employed to describe this effect. Based on quasi-static modeling, the effects of crucial parameters on the directive propagating of the confined surface wave and on its corresponding directional pattern are theoretically and numerically studied. Interestingly, the theoretical results, adequately confirmed by the computations, demonstrate that an excited plasmonic NP with a little horizontal elongation to modify internal electric polarization of the NP remarkably enhances the PSHE, resulting in almost unidirectional scattering of the launched SPP on the MDI. The findings pave a way for SPP-based engineering applications and multichannel photonic communications.

Thickness-modulated in-plane Bi2O2Se homojunctions for ultrafast high-performance photodetectors**Project supported by the National Natural Science Foundation of China (Grant No. 61705066), the Open Fund of State Key Laboratory of Information Photonics and Optical Communications (Beijing University of Posts and Telecommunications), China (Grant No. IPOC2018B004), and the National Key Research and Development Program, China (Grant No. 2016YFA0202401).

Bi2O2Se thin film could be one of the promising material candidates for the next-generation electronic and optoelectronic applications. However, the performance of Bi2O2Se thin film-based device is not fully explored in the photodetecting area. Considering the fact that the electrical properties such as carrier mobility, work function, and energy band structure of Bi2O2Se are thickness-dependent, the in-plane Bi2O2Se homojunctions consisting of layers with different thicknesses are successfully synthesized by the chemical vapor deposition (CVD) method across the terraces on the mica substrates, where terraces are created in the mica surface layer peeling off process. In this way, effective internal electrical fields are built up along the Bi2O2Se homojunctions, exhibiting diode-like rectification behavior with an on/off ratio of 102, what is more, thus obtained photodetectors possess highly sensitive and ultrafast features, with a maximum photoresponsivity of 2.5 A/W and a lifetime of 4.8 μs. Comparing with the Bi2O2Se uniform thin films, the photo-electric conversion efficiency is greatly improved for the in-plane homojunctions.

Photon Enhanced Interaction and Entanglement in Semiconductor Position-Based Qubits

CMOS technologies facilitate the possibility of implementing quantum logic in silicon. In this work, we discuss a minimalistic modelling of entangled photon communication in semiconductor qubits. We demonstrate that electrostatic actuation is sufficient to construct and control desired potential energy profiles along a Si quantum dot (QD) structure allowing the formation of position-based qubits. We further discuss a basic mathematical formalism to define the position-based qubits and their evolution under the presence of external driving fields. Then, based on Jaynes–Cummings–Hubbard formalism, we expand the model to include the description of the position-based qubits involving four energy states coupled with a cavity. We proceed with showing an anti-correlation between the various quantum states. Moreover, we simulate an example of a quantum trajectory as a result of transitions between the quantum states and we plot the emitted/absorbed photos in the system with time. Lastly, we examine the system of two coupled position-based qubits via a waveguide. We demonstrate a mechanism to achieve a dynamic interchange of information between these qubits over larger distances, exploiting both an electrostatic actuation/control of qubits and their photon communication. We define the entanglement entropy between two qubits and we find that their quantum states are in principle entangled.

Coherent poly propagation materials with 3-dimensional photonic control over visible light.

The purpose of the present research was to identify and examine materials demonstrating a previously undiscovered property of coherent poly propagation (CPP). The materials were amorphous silicates as natural precious opals. CPP enabled three-dimensional photonic control over mono and polychromatic visible light wavelengths. CPP caused coherent diffraction of incident poly and monochromatic light. Apart from the iconic play-of-color of precious opal, CPP specimens demonstrated diffractive photonic demultiplexing and/or upconversion and/or downconversion of incident light with strong photonic coherence such that the shape of the incident light source was propagated over three dimensions over multiple visible frequencies. CPP events manifested as each specimen was rocked under the incident light. Additionally, the specimens demonstrated atypical control over internally reflected and transmitted light. The specimens applied axial rotational symmetry over the incident light. Amorphous materials would be expected to exert no symmetry control. CPP and rotational properties occurred in isolation from exogenous thermal, photonic and electrical influences. Furthermore, several non-destructive analytical instruments were employed, such as: spectrophotometer, polariscope and refractometer. The analytical methods revealed unusual behaviors of these specimens. The application of materials demonstrating three-dimensional photonic control will have far-reaching implications for many industries, including: photonic wavelength demultiplexing, fiber optics, imaging, microscopy, projections, security, cryptography, computers and communications.

Strong Exciton-Plasmon Coupling and Hybridization of Organic-Inorganic Exciton-Polaritons in Plasmonic Nanocavity**Supported by the National Key Research and Development Program of China under Grant No 2016YFA0301300, the National Natural Science Foundation of China under Grant Nos 11574035 and 11374041, and the State Key Laboratory of Information Photonics and Optical Communications.

We investigate strong exciton-plasmon coupling and plasmon-mediated hybridization between the Frenkel (F) and Wannier–Mott (WM) excitons of an organic-inorganic hybrid system consisting of a silver ring separated from a monolayer WS2 by J-aggregates. The extinction spectra of the hybrid system calculated by employing the coupled oscillator model are consistent with the results simulated by the finite-difference time-domain method. The calculation results show that strong couplings among F excitons, WM excitons, and localized surface plasmon resonances (LSPRs) lead to the appearance of three plexciton branches in the extinction spectra. The weighting efficiencies of the F exciton, WM exciton and LSPR modes in three plexciton branches are used to analyze the exciton-polaritons in the system. Furthermore, the strong coupling between two different excitons and LSPRs is manipulated by tuning F or WM exciton resonances.