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The terahertz (THz) communication utilizes the frequency spectrum above 300 GHz and is widely considered as a promising solution to the future high-speed short-range wireless communication beyond millimeter wave communication. While providing tens of gigahertz bandwidth, it is subjected to high-propagation path loss, inter-symbol, and inter-user interferences. The massive multiple-input-multiple-output (MIMO) can be applied to address these problems by cooperation between many access point antennas. However, the THz channel characteristics, including high-propagation path loss, frequency selectivity, and a big number of samples per channel impulse response, require carefully tailored algorithm for massive MIMO signal processing. In this paper, we propose a single carrier minimum mean square error precoding and detection algorithm for frequency selective THz channels. The MIMO signal transmission is described with the block matrices. A gain control heuristic is introduced to reduce the complexity. The sparsity property of the channel is utilized to construct sparse channel matrices and the least square QR algorithm is applied to efficiently solve the problems. Besides the uniform antenna array, the hybrid array consisting of several subarrays is considered as well. The simulation results show that the massive MIMO array can provide a satisfactory performance in terms of bit error rate.

Graphene has been proposed to be integrated with Si Photonics because of its very high mobility, fast carrier dynamics and ultra-broadband optical properties. High speed graphene photodetectors have been demonstrated so far, however the most are based on the photo-bolometric or photo-conductive effect. These devices are characterized by large dark current, in the order of milli-Amperes. Photothermal effect (PTE) photodetectors can be used in voltage detection mode with no dark current, it is ultra fast and it operates near zero-bias. Graphene PTE-based photodetectors have been reported so far but high-speed optical telecommunication signal detection has not been shown yet. Here, we report on a graphene PTE-based photodetector on SOI waveguide. Thanks to the optimized design we show a direct detection of 105Gb/s non-return to zero (NRZ) and 120Gb/s 4-level pulse amplitude modulation (PAM) optical signals.

International audience; This paper gives an overall picture from BiCMOS technologies up to THz systems integration, which were developed in the European Research project TARANTO. The European high performance BiCMOS technology platforms are presented, which have special advantages for addressing applications in the submillimeter-wave and THz range. The status of the technology process is reviewed and the integration challenges are examined. A detailed discussion on millimeter-wave characterization and modeling is given with emphasis on harmonic distortion analysis, power and noise figure measurements up to 190 GHz and 325 GHz respectively and S-parameter measurements up to 500 GHz. The results of electrical compact models of active (HBTs) and passive components are presented together with benchmark circuit blocks for model verification. BiCMOS-enabled systems and applications with focus on future wireless communication systems and high-speed optical transmission systems up to resulting net data rates of 1.55 Tbit/s are presented.

The challenge of next generation datacom and telecom communication is to increase the available bandwidth while reducing the size, cost and power consumption of photonic integrated circuits. Silicon (Si) photonics has emerged as a viable solution to reach these objectives. Graphene, a single-atom thick layer of carbon5, has been recently proposed to be integrated with Si photonics because of its very high mobility, fast carrier dynamics and ultra-broadband optical properties. Here, we focus on graphene photodetectors for high speed datacom and telecom applications. High speed graphene photodetectors have been demonstrated so far, however the most are based on the photo-bolometric (PB) or photo-conductive (PC) effect. These devices are characterized by large dark current, in the order of milli-Amperes , which is an impairment in photo-receivers design, Photo-thermo-electric (PTE) effect has been identified as an alternative phenomenon for light detection. The main advantages of PTE-based photodetectors are the optical power to voltage conversion, zero-bias operation and ultra-fast response. Graphene PTE-based photodetectors have been reported in literature, however high-speed optical signal detection has not been shown. Here, we report on an optimized graphene PTE-based photodetector with flat frequency response up to 65 GHz. Thanks to the optimized design we demonstrate a system test leading to direct detection of 105 Gbit s-1 non-return to zero (NRZ) and 120 Gbit s-1 4-level pulse amplitude modulation (PAM) optical signals

In conjunction with their electronically reconfigurable optical properties, inorganic, WO3/LiNbO3/NiO Electro-Chromic materials (EC) have recently been shown to exhibit a degree of electric field induced dielectric tunability at radio frequencies, to the level comparable with more mature bulk-tuneable technologies. However, the full extent of their dielectric tunability remains fully unexplored, due to a fundamental lack of understanding of its intricate tuning mechanisms. The unveiling of their tuning principles is paramount towards a comprehension of not only their optical and radio frequency dielectric tunability, but also for the creation of EC structures with substantial permittivity tuning ratios. Here, we report on an inorganic, WO3 and LiNbO3 – based EC structure with perturbed constituent layers. We developed and synthesised a new EC structure by inserting the chromic layers in the interior of the device and partitioning the electrolyte layer and assigning it to the device’s peripheries. This new arrangement allows for an increase in the dielectric tunability of over three times compared to previously reported standard EC structures in the frequency range from 1–20 GHz.

Graphene is an ideal material for optoelectronic applications. Its photonic properties give several advantages and complementarities over Si photonics. For example, graphene enables both electro-absorption and electro-refraction modulation with an electro-optical index change exceeding 10$^{-3}$. It can be used for optical add-drop multiplexing with voltage control, eliminating the current dissipation used for the thermal detuning of microresonators, and for thermoelectric-based ultrafast optical detectors that generate a voltage without transimpedance amplifiers. Here, we present our vision for grapheme-based integrated photonics. We review graphene-based transceivers and compare them with existing technologies. Strategies for improving power consumption, manufacturability and wafer-scale integration are addressed. We outline a roadmap of the technological requirements to meet the demands of the datacom and telecom markets. We show that graphene based integrated photonics could enable ultrahigh spatial bandwidth density , low power consumption for board connectivity and connectivity between data centres, access networks and metropolitan, core, regional and long-haul optical communications.

A pulse-width and pulse-position modulator (PWPM) IC for RF carriers from 170 MHz to 2.8 GHz is presented. The IC features a digital 5 bit pulse-width (PW) and 6 bit pulse-center (PC) input interface, updated at the RF carrier frequency, a small arithmetic unit, two delay locked loops with a new phase detector, two phase selectors, CMOS pulse logic and two differential binary RF outputs. At 900 MHz, a 14 MBd 256-QAM (112 Mb/s) signal with an EVM of 1.83 % and an ACLR of -45 dB is shown. At 2016 MHz, an ultra-broadband 504 MBd 16-QAM (2.016 Gb/s) signal with an EVM of 13.5 % and a BER of 1.5·10-4 is demonstrated. The IC is implemented in a 28 nm fully depleted silicon-on-insulator (FDSOI) CMOS technology and runs from a 1.0 V supply. It consumes 38 mW at 900 MHz and 58 mW at 2016 MHz carrier frequency.

This paper analyses the achievable signal quality of a novel system architecture for small cell units with integrated millimetre-wave wireless backhaul over realistic link lengths. The small cell unit is mainly based on a simple frequency conversion from backhaul to access frequencies. Therefore, the data signal on the backhaul link is solely a frequency shifted version of the 3GPP compliant signal on the access link. The sufficient linearity and phase noise performance at 60 GHz was proven in an outdoor long-distance trial by measurements of an L TE signal easily meeting the 3GPP requirements for the access link. Moreover, a successful outdoor test of our full end-to-end L TE mobile communication system with a commercial user device demonstrated the required high data rates.

Electro-chromic materials (EC) are a new class of electronically reconfigurable thin films that have the ability to reversibly change optical properties by electric charge insertion/extraction. Since their discovery by Deb, they have been employed in applications related to display technology, such as smart windows and mirrors and active optical filters. In this sense, a variety of studies related to the tuneable optical characteristics of EC materials have recently been reported, however, their microwave tuneable dielectric characteristics have been left somewhat unexplored. In 2016 Bulja showed that dc bias voltage induced modulation of the optical characteristics of an inorganic Conductor/WO3/LiNbO3/NiO/Conductor EC cell isaccompanied by the modulation of its high frequency (1–20 GHz) dielectric characteristics. In general, according to the state of the art, cells of different material compositions are needed to produce devices of tailor made characteristics. Here, we report the discovery that the microwave dielectric and the optical characteristics of an EC cell can be engineered to suit a variety of applications without changing their material composition. The obtained results indicate the potential for producing novel, tuneable and tailor-engineered materials that can be used to create next generation agile microwave-optical devices.

We experimentally demonstrate Dual Polarization 64 QAM at 100 GBaud performing below the 20% soft FEC threshold of 4×10−2 over 300 km of ultra large effective area fiber at a record line rate of 1.2-Tbit/s.

We demonstrate generation of a 44 Gbaud 64 QAM dual polarization dual channel signal from one laser achieving a gross rate of 1.056 Tbit/s. Fiber transmission reach of 730 km over SSMF is also demonstrated.

Optical data links are the backbone of today’s telecommunication infrastructure. The integration of electronic and optic components on one chip is one of the most attractive routes to further increase the system performance. Here, we present the fabrication of photodetectors based on CVD-grown graphene on silicon photonic waveguides. The devices operate bias-free in the C-band at 1550 nm and show an extrinsic −3 dB bandwidth of 41 GHz. We demonstrate that these detectors work at data rates up to 50 GBit/s with excellent signal integrity.

Mobility is an important aspect in our daily life and has a deep impact on a multitude of societal factors. For nearly 120 years, we have been heavily relying on fossil energy sources. This trend may not be sustainable in the coming decades due to shortage of resources as well as ambitious goals for environmental protection. In this situation, electric vehicles could play a key role in maintaining our high level of individual mobility. After an introduction briefly depicting the motivation for change, this paper presents a state of the art analysis of the concepts driving increased deployment of electric vehicles. Based on an estimated rollout scenario of electric mobility (e-mobility) in Germany we discuss its impact on the electricity distribution grid. An algorithm for estimating energy demands caused by electric vehicles in time and location is proposed. Movement scenarios are investigated, and key parameters are defined as a baseline for this algorithm.

This paper gives a summarized overview on the progress and achievements on AlGaN/GaN high electron mobility transistors (HEMT)-based power amplifiers (PAs) for mobile radio applications which have been achieved within two national funded German projects during a period of six years. Starting with a first 34 dBm (2.5 W, peak) amplifier in 2003 the impressive progress toward highly efficient S-band mobile radio PAs with up to >50 dBm (100 W) peak output power is described by means of some selected single- and multiband amplifier demonstrators. This progress has been mainly enabled by clear progress on GaN technology, device packaging, and PA design. Targeting at highly efficient single-band amplifier applications, a 2.7 GHz symmetrical Doherty amplifier with up to 45% drain efficiency at close to 45 dBm average output power under single-carrier W-CDMA (Wideband Code Division Multiple Access) operation using digital predistortion can be highlighted. In case of multiband capable amplifiers addressing software-defined radio applications, a class-AB-based demonstrator covering a frequency range from 1.8 to 2.7 GHz was realized. The amplifier showed >30% drain efficiency up to 2.5 GHz as well as up to 40 dBm average output power under single-carrier W-CDMA operation using proprietary digital predistortion. Finally, Alcatel-Lucent's activities on envelope tracking for future efficiency improved GaN-based amplifiers are described.

This paper presents a 4th order continuous-time bandpass delta-sigma modulator (CT-BPDSM) with a programmable center frequency ranging from 1.55 GHz to 2.45 GHz. The modulator is suited to be applied in multi-standard class-S power amplifiers. The circuit features a multi-feedback architecture with return-to-zero (RZ) and half-return-to-zero (HRZ) pulses. The loop filters consist of LC-resonators with emitter degenerated input transconductors and Q-enhancement circuits. A configuration register allows to program the resonator input transconductors, the Q-enhancement circuits and the resonator capacitances with 5 bit resolution. Fine tuning of the resonator center frequency is achieved with varactors. The circuit is implemented in a 200 GHz-f T SiGe-bipolar technology. The measured SNR at 2.2 GHz center frequency is 45.5 dB in a bandwidth of 20 MHz. At 1.55 GHz the SNR decreases to 40.7 dB. The measured uplink UMTS-FDD ACLR (adjacent channel leakage power ratio) of the modulator output is 48.4 dB in the first adjacent channel.

A continuous-time bandpass delta-sigma modulator (CT BPDSM) for class-S power amplifier applications with a center frequency of 2.2 GHz is presented. Class-S amplifiers are considered to provide a very power efficient way to amplify signals with high dynamic range. The modulator has a multi-feedback architecture. It features a low noise transconductor with series emitter degeneration, tunable LC resonators with Q-enhancement and an optimized clock tree operating at 7.5 GHz. The circuit is implemented in a 200 GHz-f T SiGe-bipolar technology. A peak SNDR of 43 dB in a bandwidth of 20 MHz is measured. The circuit dissipates 450 mW from a 3.6 V supply.