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Coherent wavelength division multiplexing (WDM) transmission technique has been penetrated into the intra-data-center interconnection (Intra-DCI), due to its capability of high receiver sensitivity and efficient impairment mitigation. Here, we experimentally present a coherent WDM transmission of 40-channel 60 GBaud dual-polarization 16-level quadrature amplitude modulation (DP-16QAM) signals covering the extended C-band over 500 m homemade nested anti-resonant nodeless fiber (NANF) for high-capacity Intra-DCI. We also propose to utilize a simplified Volterra nonlinear equalizer (S-VNE) to mitigate the transmission nonlinearities originating from the transmistter hardware, resulting in 17.2% and 23% computational complextity reduction in terms of additions and multiplications with almost negligible performance penalty, in comparison with conventional VNE. As a result, the bit-error ratio (BER) of all 40 WDM channels can be lower than the 7% hard-decision forward error correction (HD-FEC) threshold of BER = 4.5×10−3. We experimentally realize a net bit-rate of 448.6 Gbit/s per wavelength and a total transmission capacity of 17.9 Tbit/s.

The performance of high-speed intensity modulation direct detection (IM-DD) transmission can be severely degraded by the optical multipath interference (MPI), due to the repeated reflections from polluted fiber connectors. Here, we propose a data-driven MPI mitigation scheme, utilizing a feedforward neural network (FNN) with the capability of powerful nonlinear mapping, after both the temporal and frequency domain MPI model are numerically investigated. Our simulation results reveal that, when the 28 Gbaud PAM-4 signals are transmitted over standard single mode fiber (SSMF), the proposed FNN can effectively mitigate the MPI and improve the transmission performance, under conditions of variable signal-interference ratios (SIRs) and various laser linewidths. Compared with recently reported non-data-driven MPI mitigation schemes, the FNN enabled MPI mitigation scheme can increase the SIR tolerance by 1.5, 1.8, and 0.8 dB, under conditions of 100 kHz, 1 MHz, and 10 MHz laser linewidth, respectively, in case the KP4-FEC threshold is considered. Meanwhile, we thoroughly study the simplification of the FNN enabled MPI mitigation scheme relying on the multiple-symbol-output (MSO) structure and weight pruning, leading to a computational complexity reduction by 32.4%, in comparison with non-data-driven MPI mitigation schemes. Finally, the performance of full-size FNN and simplified FNN enabled MPI mitigation is experimentally evaluated for the 28 Gbaud PAM-4 signals transmission over 10.81 km SSMF, observing a 2.2 and 0.9 dB improvement of SIR tolerance at the KP4-FEC threshold, respectively.

The Kramers-Kronig (KK) receiver breaks through the limitation that a single photodetector (PD) can only process the intensity information, and has become a research hotspot in optical communication system. However, in the conventional KK algorithm, the required nonlinear operations (such as logarithm (log) and exponential and square-root (sqrt) functions) significantly broadens the signal spectrum, it is necessary to employ the digital upsampling at the beginning of the digital signal processing (DSP). The high sampling rate will bring multiple hardware resources and power consumption, which becomes a major obstacle to implement KK receiver. In this paper, we propose a novel improved algorithm for the KK receiver, which does not need the digital upsampling and lowers the required carrier-to-signal power ratio (CSPR) with a comparison of the typical upsampling-free KK receiver. In the proposed improved algorithm, we adopt the mathematical approximations of Taylor's expansion and Newton's tangent method to avoid the use of log and sqrt functions. Then we removed the exponential function by expressing complex signal in Cartesian form (i.e., real plus imaginary). Whereas the real part of it is induced by employing imaginary part-induced signal-signal beat interference (SSBI) removal and sqrt operation to recover. Meanwhile, we use the simplified hybrid KK-SSBI cancellation (SHKK-SSBIC) technology to reduce the required CSPR by the system. We validate our proposed algorithm by transmitting 160 Gb/s single-sideband (SSB) signal. The experimental results show that compared with the upsampling-free KK receiver, the proposed scheme can realize the reduction of the required CSPR by 1 dB and 0.8 dB respectively under the Nyquist sampling rate at (back-to-back) BTB and 80 km transmission. Moreover, our proposed method achieves a 2 dB system sensitivity improvement in the BTB scenario. We also discuss the hardware implementation of the improved KK algorithm and its computational complexity.

The O-band operation becomes an ideal choice for the high-speed intensity modulation direct detection (IM-DD) transmission, benefitting from both a low CD and low-cost transceiver. Here, we explore the incorporation of both transmitter-side digital pre-emphasis and various receiver-side digital equalizers, in order to effectively deal with the severe inter-symbol interference (ISI) arising in the bandwidth constraint of O-band silicon photonic (SiP) transceiver and various transmission impairments after the fiber optical transmission. We experimentally evaluate the performance of various digital equalizers, including feed-forward equalizer (FFE), decision-feedback equalizer (DFE), Volterra feed-forward equalizer (VFFE), and Volterra decision-feedback equalizer (VDFE), when the pre-emphasis of SiP transceiver with a 10dB bandwidth of 21 GHz is implemented. Finally, we successfully demonstrate the optical amplifier-free 100 Gbaud PAM-4 signals transmission over 10 km SSMF, when the taps of VDFE are optimized, for the purpose of solving the trade-off between the implementation complexity and transmission performance.

The high mortality rate associated with melanoma primarily results from metastasis and recurrence. However, the precise mechanisms driving these processes remain poorly understood. Intercellular communication between cancer cells and non-cancer cells significantly influences the tumor microenvironment and plays a crucial role in metastasis. Therefore, our current study aims to investigate the role and mechanism of long non-coding RNAs (lncRNAs) in regulating the interaction between melanoma cancer stem cells (CSCs) and non-CSCs during the metastatic colonization process. This study has characterized a novel lncRNA called Gm33149. Importantly, we provide evidence for the first time that Gm33149, originating from highly metastatic melanoma stem cells (OL-SD), can be packaged into exosomes and transferred to low-metastatic nonstem cells (OL). Once internalized by OL cells, Gm33149 exerts its function through a competitive endogenous RNA mechanism (ceRNA) involving miR-5623-3p. Specifically, Gm33149 competitively binds to miR-5623-3p, thereby activating the Wnt signaling pathway and promoting the acquisition of a more aggressive metastatic phenotype by OL cells. In summary, our findings suggest that targeting lncRNA Gm33149 within extracellular vesicles could potentially serve as a therapeutic strategy for the treatment of metastatic melanoma.

Nonlinear equalization (NLE) is essential for guaranteeing the performance of an optical network (ON). Effective NLE implementation relies on key parameters of the transmission link, including the modulation format (MF) and the launch power. As ONs become more agile, the parameters of fiber optical transmission need to be adaptive and relevant to the routing condition. Therefore, successful NLE implementation relies on the realization of transmission awareness (TA). Although machine learning-enabled optical performance monitoring (OPM) has been extensively investigated in the past few years, current NLE algorithms cannot autonomously perceive transmission parameters. Furthermore, current TA implementation still needs human intervention to guide the NLE. In addition, existing ML-based OPM and NLE cannot be trained autonomously, leading to the incapability of environmental change and mislabeling. Here, we propose cognitive learning (CL) for TA-guided NLE in agile ONs. We perform an experiment involving 32 Gbaud polarization-division-multiplexed (PDM)-quadrature phase shift keying (QPSK)/16-quadrature amplitude modulation (QAM) transmission over 1500 km of standard single-mode fiber (SSMF) with a variable launch power from 0 to 3 dBm. When a deep neural network (DNN) with amplitude histograms (AHs) as inputs and one step per span-learned digital back-propagation (1stps-LDBP) are developed, the CL simultaneously enables both TA and NLE, with the capability of self-learning, mislabeling resistance, and dynamic adaptation. The proof-of-concept experimental results indicate that both the accuracy of TA and the Q-factor of PDM-16QAM can be improved by 34.8% and 0.84 dB, respectively, when the launch power is 3 dBm. Moreover, the accuracy of TA is enhanced by 35.3%, even when the used data has 30% mislabeling. Therefore, the CL framework can be customized to satisfy various NLE implementations, thereby supporting the adaptive transmission of agile ONs.

The performance of high baud-rate fiber optical transmission with the use of advanced modulation formats is sensitive to the imperfection arising in transmitter optical sub-assembly (TOSA), and thus the effective calibration of the TOSA full-field response is essential. However, traditional TOSA frequency response characterization solutions are either inconvenient for the on-field measurement or unable to obtain the phase frequency response (PFR). Here, we report a simple and precise scheme to characterize the full-field frequency response of broadband TOSA, including both amplitude frequency response (AFR) and PFR, when only a single photodetector (PD) with narrow bandwidth is employed. A multiple dual-tone signals with specially designed frequency positions are implemented for electrical-to-optical modulation. Then, a few beat signals after direct detection occur at unique frequencies without the spectral overlapping. Thus, it is feasible to extract the full-field frequency response of broadband TOSA, under the single-shot measurement. Moreover, the in-phase and quadrature (IQ) skew can be obtained by comparing PFRs between I and Q tributaries. In the experiment, we successfully characterize a coherent TOSA with a 10 dB bandwidth of 40 GHz, when a single PD with a 3 dB bandwidth of 2 GHz is used. In comparison with the optical spectrum analyzer (OSA) based scheme, the measured AFR deviation is less than 1 dB over the 10 dB bandwidth. When multiple single-shot measurements are implemented within 1 minute, the fluctuation of measured PFR and IQ skew are less than 0.2 rad and 1 ps, respectively. With the help of the measured full-field frequency response, the coherent TOSA can be calibrated to realize 64 GBaud 16-quadrature amplitude modulation (QAM) back-to-back transmission, when the threshold of 7% hard-decision forward error correction (HD-FEC) is set.

A flexible multi-band radar is proposed for simultaneous measurement of distance and velocity, based on a cavity-less ultra-short optical pulse source (CUOPS). At the transmitter, through sampling of an intermediate-frequency linear frequency modulation waveform (IF-LFMW) via the CUOPS, multi-band radio-frequency linear frequency modulation waveform (RF-LFMW) signals can be successfully generated. Meanwhile, the multi-band echo signals are de-chirped to the IF band through the mixing with the optical RF-LFMW reference signals at the receiver. When a multi-band RF-LFMW signals covering C- to Ka-band are experimentally generated, the distance measurement of static targets is achieved with both error and resolution of 0.48 cm and 30 cm, respectively. Moreover, because of the different scattering characteristics of the target at various frequency bands, simultaneous detection of multi-band RF-LFMW signals is beneficial for reducing the possibility of false target detection. Next, simultaneous distance and radial velocity measurement without ambiguity can be achieved by the use of dual-band RF-LFMW signals with opposite chirp. Both a range of 40 km and a velocity of 400 m/s are numerically verified. The most prominent advantage of the proposed scheme lies in that the operation bands can be flexibly tuned by varying the frequency of the local oscillator microwave signal at the CUOPS. Hence, the proposed scheme is promising to realize a flexible photonic-assisted multi-band radar for anti-stealth detection application.

Optical phase conjugation and mode selective conversion are indispensable for all-optical signal processing in mode-division multiplexing (MDM) transmission systems. However, manipulation in spatial mode domain based on a single-stage four-wave mixing (FWM) usually varies the operation wavelength. In this letter, we present a phase conjugated mode conversion scheme, without the parasitic wavelength conversion, enabled by two-stage cascaded FWMs. By properly incorporating the intra-modal and inter-modal FWMs, we experimentally demonstrate the phase-conjugated mode conversion between LP01 and LP11 modes at the signal wavelength of 1555.75 nm and 1541.25 nm, with a pump-signal detuning of 2.5 nm. The proposed phase conjugated mode conversion is promising to enhance the robustness and flexibility of MDM transmission systems.

Look-up table (LUT) is an efficient digital pre-distortion (DPD) technique at the transmitter side (Tx) to mitigate the pattern-dependent impairment arising in the intensity-modulation direct-detection (IM-DD) transmission. When the long-memory nonlinear inter-symbol interference (ISI) occurs for the high-speed IM-DD transmission, both the peak-to-average power ratio (PAPR) of the pre-distorted signal and the implementation complexity of LUT increases fiercely along with the growing memory length of LUT. Here, relying on the error distribution of the received symbol with respect to amplitudes of previous symbols and next symbols, we propose a low-complexity multi-symbol simplified LUT (MSS-LUT)-based DPD, by pruning the LUT entries via the pre-fixed threshold. Meanwhile, we jointly optimize the modulation depth and the clipping ratio to maximize the performance of the proposed MSS-LUT-based DPD scheme. The effectiveness of the proposed MSS-LUT-based DPD scheme is experimentally verified, under the condition of C-band four-level pulse amplitude modulation format (PAM-4) back-to-back (B2B) transmission with variable baud rates and memory lengths. When 100 GBaud/λ PAM-4 is transmitted, the size of MSS-LUT is reduced by 91.4%. This value is in comparison with the case of a full-size LUT with a memory length of 5 (LUT-5), together with only a 0.3 dB penalty of received optical power (ROP).

This communication proposes a dual-layer 2-bit phase quantization transmitarray antenna (TA) based on two pairs of orthogonal modes (TPOMs) for 77-GHz applications. In comparison to the typical multilayer configurations, the proposed element can be constructed by using only two metal layers without metallic vias. It is found that the two orthogonally placed strips of each element can construct a cavity-like structure, where TPOMs are formed. Two L-shaped slots are etched on the two strips to improve the mode coupling coefficient and each pair of orthogonal modes can achieve mutual conversion, which allows to perform the rotation of polarization in two bands. The high-frequency modes and the low-frequency modes can be adjusted to resonate at the same frequency of 77 GHz, forming a 90° phase difference. By placing the position of the L-shaped structure symmetrically, the path of the mode coupling is then reversely rotated, thus forming a 180° phase difference. Using these three approaches, the 2-bit elements are realized with good performance of wideband and low loss. To realize the beam scanning in a certain range, the phase coding of the array is optimized by the main beam control method (MBCM). Finally, a circular array with 1224 elements is fabricated. The measured results show that the designed array can maintain a relatively stable gain and beamwidth within the scanning range of ±30°.

A novel 1-bit dual-layer reconfigurable transmitarray antenna (RTA) based on two orthogonal modes is presented in this letter. In contrast to traditional multilayer designs, the proposed element has a compact structure with only two metallic layers printed on opposite sides of a single dielectric substrate. The upper and lower patches of the element form a cavity-like structure with two orthogonal modes. An L-shaped slot is loaded on the upper patch to make the structure asymmetric and the two orthogonal modes in the cavity can be converted to each other, realizing the polarization rotation. To realize a reconfigurable structure, a pair of PIN diodes are placed at both ends of the π-shaped slot (combined by an L-shaped slot and a reverse L-shaped slot) to change the direction of the mode rotation clockwise or counterclockwise. The bias network for controlling the PIN diodes is also integrated into the two metallic layers. An RTA prototype with 16 × 16 elements is designed, fabricated, and measured. The measured 3 dB bandwidth of the RTA is 21.2% from 3.8 to 4.7 GHz, with a realized gain of 18.2 dBi at 4 GHz. Good beam scanning performance has also been achieved in the E- and H-planes.

A simultaneous transmitting and reflecting reconfigurable array (STAR-RA) with independent beams is proposed in this communication. This STAR-RA can realize bidirectional beams simultaneously and the forward and backward beam directions can be controlled independently. To realize this function, a novel element consisting of the forward and backward phase-controlling patches is proposed. With the help of two pairs of p-i-n diodes, it divides the incident wave into a 1 bit reconfigurable reflecting part and a 1 bit reconfigurable transmitting part. Further, a STAR-RA prototype with $16\times16$ elements is designed, fabricated, and measured. The measured results show a good beam-scanning capability of ±60° with a maximum gain fluctuation of 5.5 dB in E- and H-planes for both the transmitting and reflecting beams. The 1 dB gain bandwidth of the STAR-RA is 8.4% from 5.7 to 6.2 GHz. The distinctive advantage of the proposed design is the independently controlled bidirectional beams that work simultaneously, which is suitable for bidirectional wireless communication applications.

Short-time Fourier transform (STFT) is a vital tool to observe spectral dynamics of non-stationary signals. Conventional STFT based on digital signal processing (DSP) usually suffers from a limited acquisition frame rate within 106 Fourier transforms per second (FTs/s). Thus, it is unable to fully intercept transient information in time and frequency shorter than a few microseconds. Further extending the acquisition frame rate can be achieved by employing the dispersion-based all-optical spectral analysis approach, while the optical dispersion usually introduces a large latency. Here, we experimentally report a low-latency STFT of microwave photonic processing, where a passive fiber loop is used to provide high value equivalent dispersion. Consequently, the latency of the STFT processing can be greatly reduced. The spectrograms of microwave signals, including instantaneous information in both time and frequency, are acquired in a real-time manner, with an acquisition frame rate of about $5 \times {10}^8$ FTs/s and a processing latency of less than 0.2 ${{\bf \mu s}}$. High temporal resolution within tens of nanosecond range can be achieved, allowing us to capture 30-ns duration frequency transients in real time with a instantaneous bandwidth of about 530 MHz. Our proposed STFT processing scheme is promising for real-time and high-speed spectral dynamic analysis for non-stational signals.

Phase-retrieval (PR) receivers can reconstruct complex-valued signals from two de-correlated intensity measurements by the use of iterative PR algorithm, without the assistance of any optical carriers. However, both the computational complexity with hundreds of iterations and the limited PR accuracy prevent it from being applied to high-speed photonic interconnections. In current submission, we propose a weighted decision enhanced PR receiver with adaptive intensity transformation (WD_AIT_PR). The weighted decision based on a compressed sigmoid nonlinear function is helpful to avoid the hard-decision (HD) errors, leading to the performance enhancement of the PR receiver, in terms of both convergence speed and PR accuracy. When the 56 GBaud 16QAM signal after transmission over 80 km standard single mode fiber (SSMF) is reconstructed, the WD_AIT_PR receiver is numerically verified to possess the faster convergency speed with only 70 iterations and the best steady BER performance by reducing the required optical signal-to-noise ratio (OSNR) by 0.8 dB, 1.8 dB and 1.8 dB in order to reach 7% HD forward error correction (HD-FEC), in comparison with the HD_AIT_PR receiver by replacing WD with HD, the PR receiver with the phase reset (PR_PR) and the PR receiver with adaptive intensity transformation (AIT_PR), respectively. Meanwhile, the WD_AIT_PR receiver is robust to transmission impairments, including transmitter-side I/Q imbalance, receiver-side skew, the noise imbalance between two intensity measurements, laser phase noise, and laser wavelength drift. Finally, the enhanced performance of the WD_AIT_PR receiver is experimentally verified through recovering 25 GBaud 16QAM signals under the condition of 40 km SSMF transmission.

Nowadays, effective measures are needed to reduce the harm caused by electromagnetic pollution and microplastic (MP) pollution in a water environment. Besides, since the COVID-19 pandemic in 2019, people have made a lot of progress in the recycling of waste face mask (FM) pollution. However, so far, no publications are available in the literature that simultaneously solve the problem of MP pollution, electromagnetic pollution, and FM pollution. Herein, FMs, polyethylene MPs (PE MPs), and carbon nanotubes (CNTs) were used to fabricate EMI shielding composites with an isolated conductive network structure via the adhesion ability of polydopamine (PDA). The effects of isolated conductive networks, different sizes of PE MPs, and different layers of FMs on the adsorption behavior of FMs–PDA–CNT, as well as electrical performance for the obtained PP–PDA–CNT composites, were studied. The composites displayed the EMI SE for 25.9 dB in the X-band with a 3 wt % CNT content due to the isolated conductive network structure, which may be useful to the simultaneous elimination of garbage from the electromagnetic pollution, FM pollution, and MP pollution to a certain degree.

Nonlinear impairments emerging from both fiber optical links and optoelectrical devices are the major bottleneck for enhancing the throughput of photonic data-center interconnection (DCI). Here, we propose a data-driven nonlinear equalizer based on a conditional generative adversarial network (c-GAN) for high-speed and large-capacity photonic DCI. Its performance is experimentally evaluated by transmitting C-band 40-channel 60-GBaud dual polarization-16 quadrature amplitude modulation (DP-16QAM) dense wavelength division multiplexing (DWDM) signals over 20-km standard single-mode fiber (SSMF). Our experimental results verify that, the proposed c-GAN equalizer outperforms both traditional nonlinear equalizers and other data-driven counterparts, in terms of both the bit-error ratio (BER) and computational complexity. Only the proposed c-GAN equalizer can guarantee the BER performance of all 40 channels to reach the threshold of 20% soft decision forward error correction (SD-FEC) at BER = 0.027, leading to a net transmission capacity of 16 Tb/s. Meanwhile, the computational complexity of the proposed c-GAN equalizer can be significantly reduced by 31.8%, 80.7%, and 98.8%, respectively, in comparison with Volterra filter equalizer (VFE), multilayer perceptron (MLP), and long short-term memory neural network (LSTM-NN) schemes.

In recent years, nonlinear Fourier transform (NFT) has been intensely researched as a scheme for communication over the nonlinear optical fiber and characterizing dynamics in nonlinear optical systems. For the accurate computation of b-coefficients on discrete eigenvalues, the bidirectional algorithm has been proposed where b-coefficients are calculated at a cutting point within the temporal window rather than two boundaries. The performance of the bidirectional algorithm depends severely upon the selection criterion of the cutting-point, which has been investigated in nonlinear Schrodinger equation and Korteweg–De Vries equation but not yet in Manakov equation accounting for the dual-polarization signals over optical fiber. In this paper, we propose a cutting-point criterion of b-coefficients for the bidirectional algorithm of Manakov equation and compare it with existing criteria. Numerical results show that, the resulting algorithm has much better accuracy compared with existing criteria, especially for signals containing a large number of eigenvalues with large imaginary parts. The bidirectional algorithm with the proposed criterion is useful for decoding the dual-polarization nonlinear frequency division multiplexing (DP-NFDM) signals for communication and characterization of vector soliton dynamics in Manakov equation described systems.

Optical performance monitoring (OPM) by leveraging artificial neural network (ANN) has become a promising data-driven solution for stability, reconfiguration, and efficient utilization of heterogeneous optical networks. The implementation complexity as well as the involved dataset of conventional ANN, however, remains a common concern, preventing the efficient OPM implementation. Nonlinear activation functions (NAFs) are commonly used in conventional ANN for feature attraction and nonlinear mapping, which largely reduce the convenience of the OPM, posing the question on the feasibility of removing NAF in ANN-enabled OPM. Here, by investigating the necessity of NAF for the ANN-based OPM, we find that, when either amplitude histogram (AH) or asynchronous delay-tap sampling portrait (ADTP) is used as the ANN input, the commonly-used multi-layer perceptron (MLP) and convolutional neural network (CNN) can be implemented without NAFs. Acceptable variations of mean absolute error (MAE) for the OSNR monitoring are observed by 0.03 dB and 0.23 dB, respectively. Moreover, the removal of NAF does not affect the identification of both the baud-rate and the modulation format information. Our results reveal that, the linear mapping is sufficient to realize the OPM with stable statistical images, thus leading to a simplification prospect for the on-chip ANN-enabled OPM.

Probabilistic constellation shaping (PCS) brings unprecedented flexibility to future optical networks. However, PCS combined with higher-order modulation formats and higher symbol rates puts more demands on the transmitter. For metro-transmission with high spectral efficiency (SE), transmitter impairments are responsible for a major portion of the system constraints. To address this issue, in this work we study the impact of transmitter impairments on probabilistically shaped quadrature amplitude modulation (PS-QAM) signals. First, we investigate the impact of transmitter impairments and radio frequency (RF) amplifier noise on the optimum shaping factor and the modulation depth within a fiber link. Then, we explore how generalized mutual information (GMI) and the shaping factor are affected by the noise from the transmitter. Next, we first jointly optimize the arcsine swing and the clipping ratio, in order to mitigate the transmitter impairments for the PS-QAM signal, when the modulation depth, the noise from the transmitter, the noise from the fiber optical channel, and the shaping factor are fixed. Then, we verify its validity for various configurations of transmission system. The optimized parameters primarily depend on the noise from the transmitter and turn out to be insensitive to the noise from the fiber optical link and the shaping factor. Finally, we experimentally verify the optimization strategy with PS-256QAM in back-to-back (B2B) transmission.

Transmitter dispersion eye closure quaternary (TDECQ) is one of the most important parameters that can systematically evaluate the signal quality of four-level pulse amplitude modulation format (PAM-4) transmitters. We experimentally demonstrate the acceleration of TDECQ assessment by deep transfer learning (DTL) technique. With the help of amplitude histograms (AHs) generated by the received PAM-4 signal, we are able to characterize the TDECQ value directly by the deep neural network (DNN). To further reduce both the computation time and the experimental data used for the training, simulation data can be used to provide the suitable source domain for the DTL implementation. The experimental results of 25 Gbaud PAM-4 signals indicate that, the mean absolute error of TDECQ assessment is below 0.18 dB over a TDECQ range from 1.9 to 3.6 dB. Meanwhile, 33.3% amount of the used experimental data and 40% epochs can be simultaneously reduced during the training process, due to the use of DTL.

In this article, a folded low-profile wideband 1-bit reconfigurable transmitarray (RTA) with 2-D beam-scanning capacity is proposed. To reduce the profile of the whole RTA, the ray tracking mechanism and the feed optimization are introduced. A 1-bit wideband RTA element with polarization selection function and polarization rotation function is designed based on a regular hexagonal resonant patch and p-i-n diodes. Furthermore, a specially designed waveguide structure is fabricated to verify the performance of the RTA element. To achieve the low-profile design, a wideband polarization rotation reflectarray (PRRA) element acting as the reflecting surface is proposed, and a $2\times $ 2 U-slotted planar patch antenna is designed to replace the horn. With these designs, the profile can be compressed by two-thirds compared with the conventional space-fed architecture. A $16\times16$ -elements low-profile RTA is designed and fabricated. The measured and simulated radiation patterns are in good agreement. The measured peak gain is 19.6 dB, corresponding to an aperture efficiency of 13.8%, and the measured 3 dB gain bandwidth is 17.5% (from 15.1 to 18 GHz). Good scanning performance with ±60° scanning coverage in both principal planes has been obtained, and the scan losses are 3.97 and 4.15 dB, respectively. Besides, the measured sidelobe levels (SLLs) and cross-polarization levels remain better than −15 and −20 dB, respectively, at all beam directions.

Surface interactions between a polymer and filler dictate the properties of polymer nanocomposites, yet molecular-level understanding remains a challenge. Here, we show that the glass transition temperature (Tg) of a polymer nanocomposite composed of poly(2-vinylpyridine) and polyhedral oligomeric silsesquioxanes (POSSs) with a variable number of hydrogen bond-donating amines is well explained by the product of the number of interaction sites (namine) and the POSS volume fraction (ϕPOSS). The glass transition temperature of the nanocomposites found by coarse-grained simulations agrees reasonably well with experimental results of differential scanning calorimetry, indicating that the excess interaction energy from hydrogen bonds is responsible for the change in Tgin the system. All-atom molecular dynamics simulations reveal that the number of hydrogen bonds is approximately proportional to namine, though the amines on POSSs with lower namineare able to form slightly more hydrogen bonds than POSSs with higher naminedue to geometric frustrations of polymers bonding to two adjacent bond donors. Expanding this atomic perspective to other polymer nanocomposites could lead to advancements in materials development.

We present a study of all-optical light manipulation arising in a graphene-embedded side-polished fiber (SPF) with a Norland Optical Adhesives (NOA)-coated structure. With the help of the Pauli blocking effect, such an all-fiber device serves to manage the loss of transverse-electric-polarized light when the control light and the signal light are polarized along the direction parallel to the graphene surface. The insertion loss of this device can be effectively reduced with the NOA coating. An enhanced interaction between the graphene and the propagated light can be achieved via the strong evanescent field of the SPF and longer interaction length. This results in effective all-optical manipulation of light with a modulation depth of 10.4?dB (or modulation efficiency of ∼91%) and a modulation slope of ∼1.3, where the required control power is only about 14 dBm. The device has broadband operation wavelength. The insertion loss for both the signal light and the control light are only about 0.6?dB. The experimental results are well-fitting with the simulation study. Such an all-fiber device has the potential for all-optical signal processing.

Tunable microwave dispersion is highly desired for a wide field of microwave signal processing. However, a conventional microwave dispersive delay line usually suffers from either a small dispersion value or a narrow operation bandwidth. Here, we experimentally demonstrate the optically magnified dispersion of a microwave signal with a wide and flexible tunable range, based on a bandwidth-scaling microwave photonic system. The obtained microwave dispersion can therefore be magnified from the corresponding optical dispersion with a magnification factor that can be continuously tuned from 10,000 to 85,000. Meanwhile, a proof-of-concept experiment that includes both compression and stretching of chirped microwave pulses is reported. Microwave dispersion from 1.34?ns/GHz to 10.92?ns/GHz can be secured by the corresponding magnification of an optical dispersion value of 16 ps/nm.

Deep neural networks (DNNs) have been successfully applied for accurate optical signal-to-noise ratio (OSNR) monitoring. However, the performance of OSNR monitoring substantially degrades when a mega dataset is inaccessible. Here, we demonstrate an accurate OSNR monitoring scheme based on a data-augmentation (DA)-assisted DNN with a small-scale dataset. When a 20 GBaud quadrature phase shift keying (QPSK) signal is transmitted over 400 to 2600 km standard single-mode fiber (SSMF) with an OSNR range from 8 to 14 dB, we experimentally evaluate the minimum dataset size to secure a mean absolute error (MAE) of OSNR monitoring less than 1 dB. The DA-assisted scheme only requires 50% of the raw data, in comparison with the traditional DNN scheme. Thus, the DA-assisted DNN scheme is promising for field-trial accurate OSNR monitoring, especially when the collection of mega datasets is inconvenient.

Efficient co-transmission of 10-W power light and optically carried 5G new radio (NR) signal over standard single-mode fiber (SSMF) is experimentally demonstrated, with an optical power transmission efficiency (OPTE) of power light up to 71.8%. This efficiency record is enabled by carefully manipulating the linewidth of the power light and appropriately adjusting the wavelength spacing between the power light and 5G NR optical signal to effectively mitigate the nonlinear effect arising in the SSMF. In the experiment, the optically carried 5G NR 64-level quadrature amplitude modulation orthogonal frequency division multiplexing signal at 1550 nm, with a data rate of 1.5 Gbit/s, is successfully co-propagated with 10-W power light at 1064 nm over 1-km SSMF. The error-vector magnitude (EVM) is 0.48% under a received electrical power of −25dBm. In comparison with back-to-back transmission, only slight EVM degradation of 0.02% is observed, showing that the 5G NR optical signal is almost unaffected by the existence of power light. Moreover, the power fluctuation of the collected power light is less than 0.2% over 6 h, while the EVM fluctuation is smaller than 0.01% within 30 min. Our scheme is promising to realize an optically powered remote antenna unit through the existing 5G fronthaul SSMF link.

Phase-retrieval (PR) receivers can reconstruct complex-valued signals from two de-correlated intensity measurements, without the assistance of any optical carriers. However, both the calculation complexity with hundreds of iterations and the limited PR accuracy prevent it from being applied to high-speed photonic interconnections. Here we propose and demonstrate a PR receiver based on adaptive intensity transformation, with the capability of both fast convergence and high accuracy. Then we numerically reconstruct 56 GBaud QPSK signals after the 80 km standard single-mode fiber transmission by using our proposed PR receiver with only 50 iterations. In comparison with the recently reported PR receiver with the phase reset, our proposed PR receiver can reduce the required optical signal-to-noise ratio by 1.95 and 1.89 dB, in terms of 20% soft-decision and 7% hard-decision forward-error correction, respectively.

We have demonstrated a data-driven TDECQ assessment scheme based on L-SNN. In comparison with existing DL-based schemes, the proposed L-SNN can achieve the lowest computation complexity with only 210 multiplications. The MAE of the L-SNN scheme for 25 and 50 Gbaud PAM-4 optical signals is experimentally verified to be 0.13 and 0.15 dB, respectively, over the TDECQ range of 1.5–4.0 dB, which has reached the accuracy threshold of 0.25 dB recommended by the IEEE standard.

This study aimed to determine the mechanism of isogeneic‐induced pluripotent stem cells (iPSCs) homing to vascular transplants and their therapeutic effect on chronic allogeneic vasculopathy. We found that integrin β1 (Intgβ1) was the dominant integrin β unit in iPSCs that mediates the adhesion of circulatory and endothelial cells (ECs). Intgβ1 knockout or Intgβ1‐siRNAs inhibit iPSC adhesion and migration across activated endothelial monolayers. The therapeutic effects of the following were examined: iPSCs, Intgβ1‐knockout iPSCs, iPSCs transfected with Intgβ1‐siRNAs or nontargeting siRNAs, iPSC‐derived ECs, iPSC‐derived ECs simultaneously overexpressing Intgα4 and Intgβ1, iPSCs precultured in endothelial medium for 3 days (endothelial‐prone stem cells), primary aortic ECs, mouse embryonic fibroblasts, and phosphate‐buffered saline (control). The cells were administered every 3 days for a period of 8 weeks. iPSCs, iPSCs transfected with nontargeting siRNAs, and endothelial‐prone stem cells selectively homed on the luminal surface of the allografts, differentiated into ECs, and decreased neointimal proliferation. Through a single administration, we found that iPSCs trafficked to allograft lesions, differentiated into ECs within 1 week, and survived for 4‐8 weeks. The therapeutic effect of a single administration was moderate. Thus, Intgβ1 and pluripotency are essential for iPSCs to treat allogeneic vasculopathy. Induced pluripotent stem cells and endothelial‐prone stem cells inhibit chronic allogeneic vasculopathy by differentiating into endothelial cells on the luminal surface of mouse carotid allografts in an integrin beta‐1–dependent manner.

Because only a handful of agrochemicals can manage bacterial infections, the discovery and development of innovative, inexpensive, and high-efficiency antibacterial agents targeting these infections are challenging. Herein, a series of novel epimeric and chiral 18β-glycyrrhetinic acid (GA) ester derivatives with various tertiary amine pendants were designed, synthesized, and screened for pharmacological activity. Results showed that some of the title compounds were conferred with significantly enhanced antibacterial activity toward phytopathogens Xanthomonas oryzaepv oryzae(A2, B1–B3, and C1, EC50values within 3.81–4.82 μg/mL) and Xanthomonas axonopodispv citri(B1, EC50= 3.18 μg/mL; B2, EC50= 2.76 μg/mL). These activities are superior to those of GA (EC50> 400 μg/mL), thiodiazole copper, and bismerthiazol. Pharmacophore studies revealed that the synergistic combination of GA skeleton and tertiary amine scaffolds contributed to the biological actions. In vivo experiments displayed their promising applications in controlling bacterial infections. Antibacterial mechanism studies revealed that the title compounds could trigger apoptosis in the tested pathogens, evident by bacteria morphological changes observed in scanning electron microscopy images. This outcome should motivate the development of various apoptosis inducers against plant bacterial diseases by a novel mode of action compared to that of existing agricultural chemicals.

We investigate the influence of slide rings on the stretching behavior of a single-chain polyrotaxane anchored by a fix ring. The extension of the force side in our simulations is in line with the previous theoretical framework. However, the end-to-end distance on the free side shows a discrepancy. To address this, we include the excluded-volume effect, successfully aligning with theoretical predictions. We propose a comprehensive model that incorporates excluded-volume effects for rings on both the free side and the force side. The model demonstrates qualitative consistency with simulation data, highlighting the competition among rings from each side. The force-side rings exert a significant influence on the extension of the force side, as derived from the excluded-volume effects. These findings of greater force responsiveness of force-side rings have potential implications for the design of slide-ring gels.

Regulating the position and sliding dynamics of rings on the polyrotaxane (PR) backbone plays a crucial role in determining the properties and/or functions of PR and PR-based soft materials. In this work, we use molecular dynamics simulations to reveal that the features of localization and sliding dynamics of rings on a PR modeled by a rod–coil–rod triblock copolymer are regulated by the entropy effect of the coil block. The distribution of the rings along the rod–coil–rod PR backbone is found to be highly heterogeneous and can be described by a two-state model characterized by a (free) energy gap, ΔE, which depends on the three characteristic parameters of the PR system, ΔE= ΔE(α, μ, ρring), where α is the ratio of the rod to the coil strand length, μ is a quantity of measuring the stretching degree of the coil block, and ρringis the overall ring coverage along the PR backbone. A theoretical model is proposed to describe the origin of this universality, the prediction of which is quantitatively consistent with simulation results for the single-ring rod–coil–rod PR system. The existence of an energy gap also gives a model for the dynamics of ring sliding along the PR backbone.

The emergence and widespread occurrence of plant bacterial diseases that cause global production constraints have become major challenges to agriculture worldwide. To promote the discovery and development of new bactericides, imidazole-labeled 1,3,4-oxadiazole thioethers were first fabricated by integrating the crucially bioactive scaffolds of the imidazole motif and 1,3,4-oxadiazole skeleton in a single molecular architecture. Subsequently, a superior antibacterial compound A6was gradually discovered possessing excellent competence against plant pathogens Xanthomonas oryzaepv oryzaeand Xanthomonas axonopodispv citriwith EC50values of 0.734 and 1.79 μg/mL, respectively. These values were better than those of commercial agents bismerthiazol (92.6 μg/mL) and thiodiazole copper (77.0 μg/mL). Further modifying the imidazole moiety into the imidazolium scaffold led to the discovery of an array of potent antibacterial compounds providing the corresponding minimum EC50values of 0.295 and 0.607 μg/mL against the two strains. Moreover, a plausible action mechanism for attacking pathogens was proposed based on the concentration dependence of scanning electron microscopy, transmission electron microscopy, and fluorescence microscopy images. Given the simple molecular structures, easy synthetic procedure, and highly efficient bioactivity, imidazole (or imidazolium)-labeled 1,3,4-oxadiazole thioethers can be further explored and developed as promising indicators for the development of commercial drugs.

Aptamers for Ebola virus (EBOV) offer a powerful means for prevention and diagnostics. Unfortunately, few aptamers for EBOV have been discovered yet. Herein, assisted by magnetism-controlled selection chips to strictly manipulate selection conditions, a highly efficient aptamer selection platform for EBOV is proposed. With highly stringent selection conditions of rigorous washing, manipulation of minuscule amounts of magnetic beads, and real-time evaluation of the selection effectiveness, the selection performance of the platform was improved significantly. In only three rounds of selection, the high-performance aptamers for EBOV GP and NP proteins were obtained simultaneously, with dissociation constants (Kd) in the nanomolar range. The aptamer was further applied to the detection of EBOV successfully, with a detection limit of 4.2 ng/mL. The whole detection process that consisted of sample mixing, separation, and signal acquisition was highly integrated and conducted in a magnetism-controlled detection chip, showing high biosafety and great potential for point-of-care detection. The method may open up new avenues for prevention and control of EBOV.