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Commercial coherent receivers utilize balanced photodetectors (PDs) with high single-port rejection ratio (SPRR) to mitigate the signal-signal beat interference (SSBI) due to the square-law detection process. As the symbol rates of coherent transponders are increased to 100 Gbaud and beyond, maintaining a high SPRR in a cost-effective manner becomes more and more challenging. One potential approach for solving this problem is to leverage the concept of single-ended coherent receiver (SER) where single-ended PDs are used instead of the balanced PDs. In this case, the resulting SSBI should be mitigated in the digital domain. In this paper, we show that SSBI can be effectively mitigated using various low-complexity techniques, such as the direct filed reconstruction (DFR), clipped iterative SSBI cancellation (CIC) and gradient decent (GD). In addition, we present a self-calibration technique for SERs which can be extended for characterizing the optical-to-electrical (O/E) response of a conventional balanced coherent receiver (BR). Using the developed techniques, we then experimentally demonstrate a 90 Gbaud probabilistically constellation shaped 64-QAM (PCS-64QAM) transmission using a SER, achieving a net data rate of 882 Gb/s over 100 km of standard single mode fiber (SSMF). The sensitivity penalty compared to the BR is below 0.5 dB. We expect that when the symbol rate is increased further, a SER can potentially outperform a BR, especially when applied to cost-sensitive commercial pluggable coherent transceivers

The promise of future generations of mobile communication, both 5.5 and 6G, is that of continued increases in capacity and coverage of the wireless communication network together with novel applications demanding higher levels of performance between the mobile devices and their applications on servers in the cloud. In addition, the growing shift towards virtualization of network function itself offers perhaps the most stringent requirements on the network. To continue to offer ever higher capacities and speeds, future networks will be required to further densify addressing capacity and coverage demands through the use of small cells or new radio spectral bands, such as 7-20GHZ or sub-THZ, with inherently shorter range. Therein lies the dilemma. A denser and ever more complex network of access points, with higher speeds and performance, but continued pressure on the deployment and costs. To address this challenge solutions which address all aspects of the End to End network must be considered together the mobile access points, transport networks, deployment options, and edge cloud all contribute equally to the success of the new consumer and industrial applications promised for next generation networks as well as the operation of the networks themselves. In this paper we will outline the expected requirements of next generation networks as well as new technologies and methods which address the simultaneous challenges of higher capacity, lower costs, and reliable deterministic performance.

Multiple access interfaces are required to provide the wireless coverage and capacity that operators need for consistent service across their geographic footprint. As a consequence, future radio access networks will be hybrid 4G/LTE-5G networks. This technology evolution is creating many challenges in the mobile fronthaul (MFH) networks to support the co-existence of common public radio interfaces (CPRI) and evolved common public radio interfaces (eCPRI) traffic with diverse connectivity requirements in term of capacity and reach. To address these challenges, this paper introduces a 100 Gb/s discrete multi-tone modulation (DMT) ASIC which has been designed and fabricated in 16 nm CMOS process, specifically targeting MFH applications. This DMT ASIC can flexibly support various important data rates in hybrid 4G/LTE-5G MFH networks, including CPRI-10, 25 GbE, 50 GbE, 75 GbE, and 100 GbE (eCPRI rates) over the full industrial temperature range (−40 °C to +85 °C). We demonstrate the high performance and reliability of this DMT ASIC in several real time transmission experiments, including: i) 200 Gb/s LAN-WDM2 transmission over 20 km in O-band using two 25-GHz class directly modulated lasers (DMLs); and ii) 200 Gb/s, 300 Gb/s and 400 Gb/s WDM transmissions over up to 40 km in C-band using 4 wavelengths, each with data rate of 50 Gb/s, 75 Gb/s, and 100 Gb/s, respectively. The success of these experiments clearly indicates the attractiveness of the presented DMT ASIC for future MFH applications. In addition, in several transmission scenarios, the advantages of DMT format over conventional PAM4 format for MFH applications are highlighted.

One of the widely used prominent biometric techniques for identity authentication is Face Recognition. It plays an essential role in many areas, such as daily life, public security, finance, the military, and the smart school. The facial recognition task is identifying or verifying the identity of a person base on their face. The first step is face detection, which detects and locates human faces in images and videos. The face match process then finds an identity of the detected face. In recent years there have been many face recognition systems improving the performance based on deep learning models. Deep learning learns representations of the face based on multiple processing layers with multiple levels of feature extraction. This approach has made sufficient improvement in face recognition since 2014, launched by the breakthroughs of Deep Face and Deep ID. However, finding a way to choose the best hyperparameters remains an open question. In this paper, we introduce a method for adaptive hyperparameters selection to improve recognition accuracy. The proposed method achieves improvements on three datasets.

Distributed data-center networks rely on power and cost-efficient high-speed fiber optical connections over distances up to 80 km which can be densely wavelength-division multiplexed (WDM) in the C-band. Recently, single-sideband (SSB) direct detection (DD) has been considered as an attractive transmission scheme for achieving data rates beyond 100 Gb/s per channel over 80 km. The advantages of SSB DD transmission include its simple transceiver architecture and its capability of electronic dispersion compensation. However, SSB transmissions require a carrier-to-signal power ratio (CSPR) of around 10 dB, even when signal-signal beat interference (SSBI) cancellations are applied. This high CSPR value reduces the power efficiency of the system and limits the total number of WDM channels and accordingly the total system capacity due to power limitation of optical amplifiers. In this article, we propose an iterative SSBI cancellation scheme, which can be effectively applied without digital upsampling at low CSPR values. Using this technique, we have experimentally demonstrated a 30 Gbaud 128 QAM SSB direct detection transmission over 80 km with a low CSPR of 5 dB, showing 4.6 dB performance improvement compared to the Kramers–Kronig scheme operated without digital upsampling.

Due to the growing demand for cloud services with high availability, high connection speed and low latency, distributed data-centers have emerged as a key architecture for future optical networks. This architecture relies on power and cost-efficient solutions for 400 Gb/s client interfaces over distances up to 80 km which can be densely wavelength-division multiplexed (WDM) in the C-band. Recently, single side band (SSB) direct detection (DD) has been considered as an attractive transmission scheme for achieving data rates beyond 100 Gb/s per channel due to its capability of electronic dispersion compensation. However, as SSB DD schemes utilize only a single polarization for data transmission, achieving 400 Gb/s per channel requires a baudrate beyond 80 Gbaud, which might reduce the effectiveness of the commonly used signal-signal beat interference (SSBI) cancellation techniques such as iterative SSBI cancellation or Kramers-Kronig algorithm due to the imperfection of Tx drivers, modulator and Rx front-end. In this paper, through effective Tx calibration and Rx DSP, we have achieved for the first time a net data rate per channel above 400 Gb/s with a 64 QAM signal at 85 Gbaud using a single photodetector (PD) at the receiver. In addition, a WDM transmission consisting of 5 channels at 100 GHz spacing was successfully conducted. This result indicates that SSB DD is an effective transmission technique for high capacity data center interconnect (DCI) applications.

Thin-film lithium niobate electro-optic modulators with bandwidths >100 GHz are demonstrated. The trade-off between bandwidth and voltage is alleviated by non-symmetric positioning of waveguides with respect to electrodes and by incorporating a dielectric buffer layer.

Pleuromutilin is a fungal diterpene natural product with antimicrobial properties, semisynthetic derivatives of which are used in veterinary and human medicine. The development of bacterial resistance to pleuromutilins is known to be very slow, which makes the tricyclic diterpene skeleton of pleuromutilin a very attractive starting structure for the development of new antibiotic derivatives that are unlikely to induce resistance. Here, we report the very first synthetic modifications of pleuromutilin and lefamulin at alkene position C19–C20, by two different photoinduced addition reactions, the radical thiol-ene coupling reaction, and the atom transfer radical additions (ATRAs) of perfluoroalkyl iodides. Pleuromutilin were modified with the addition of several alkyl- and aryl-thiols, thiol-containing amino acids and nucleoside and carbohydrate thiols, as well as perfluoroalkylated side chains. The antibacterial properties of the novel semisynthetic pleuromutilin derivatives were investigated on a panel of bacterial strains, including susceptible and multiresistant pathogens and normal flora members. We have identified some novel semisynthetic pleuromutilin and lefamulin derivatives with promising antimicrobial properties.