Error-free Operation Research Articles

A 112-Gb/s PAM-4 Low-Power Nine-Tap Sliding-Block DFE in a 7-nm FinFET Wireline Receiver

Practical realization of decision feedback equalizers (DFEs) has to date been limited to at most two taps in 100-Gb/s long-reach (LR) wireline applications due to significant power, area, and timing costs. This article presents a systolic many-tap low-complexity sliding-block decision feedback equalizer (SB-DFE) that overcomes the implementation challenges of conventional DFEs with no performance loss. A nine-tap configuration is demonstrated in a 112-Gb/s analog-to-digital converter (ADC)-digital signal processing (DSP) four-level pulse amplitude modulation (PAM-4) LR wireline receiver implemented in 7-nm FinFET. The architecture partitions the received signal into overlapping but computationally independent blocks thereby breaking the feedback loop of the DFE and allowing logic pipelining. Unlike existing feedback-breaking techniques, the computational overhead of the SB-DFE can be made arbitrarily small for any tap count—indeed, we show the practicality of SB-DFE implementations exceeding 30 taps. Optimized pipeline cuts are employed to minimize the latency through the SB-DFE while maintaining timing margin. The nine-tap SB-DFE is paired with a five-precursor tap feedforward equalizer (FFE) and compared to a two-tap-DFE 15-tap-FFE reference DSP implemented in the same receiver. A bit error rate of 2 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times $ </tex-math></inline-formula> 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−12</sup> is measured over a 36-dB loss channel—at least an order-of-magnitude reduction compared to the reference DSP. Power is reduced by 0.33 pJ/b. DSP gate area is reduced by 30%. Noise tolerance is improved by 0.2-mV <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RMS</sub> . Error-free operation is demonstrated on an RS(544,514) KP4 forward error correction (FEC)-encoded link even when the DFE tap values are manually stressed. Techniques for further reduction in complexity are described.

Influence of mountain traffic conditions on the functional state of a bus driver

Ensuring the transport process requires proper interaction of all parts of the system "driver - car - road - environment" and its subsystems. In this case, the driver is often a "weak" component of the system, and his actions can reduce the level of road users` safety. It should be noted that the reliability of the driver can be considered as the probability of his trouble-free and error-free operation, as well as the proper level of his regulatory mechanisms functioning. In this case, to analyze the activities and readiness of the driver for his professional activities, indicators of functional status are often used. Thus, the study of the "human factor" in the transport process is an important task to ensure the reliability of the whole transport system. Today the most of all transportation is carried out by road. The timeliness and safety of cargo delivery and passenger safety depend on the driver's actions. At the same time, the driver is influenced by a considerable number of external environmental factors during his work. One of the most important factors is the mountainous traffic conditions, which often have many changes in plan and the profile of roads. Another feature of such traffic conditions is the height above sea level, affecting the human body, particularly its functional state. Considering the above, the paper measures the heart rate variability of bus drivers moving on a route that was partly in the mountain's conditions. During the research, video recording and registration of the vehicle's geolocation were also carried out. This made it possible to establish indicators of the driver`s functional state in specific periods. After processing the obtained values, the influence of mountainous traffic conditions on the bus drivers` indicator of regulatory systems’ activity was established.

A 10.4–16-Gb/s Reference-Less Baud-Rate Digital CDR With One-Tap DFE Using a Wide-Range FD

A 10.4-16-Gb/s reference-less and baud-rate clock and data recovery (CDR) circuit with a one-tap speculative decision feedback equalizer (DFE) is presented. The quarter-rate CDR circuit uses a pattern-based phase detector (PD) and the proposed FD. This wide-range FD is composed of a coarse FD and a fine FD (FFD) which share the same front-end comparators with the PD and the DFE. Thus, no extra comparators are required. In addition, by monitoring the drift direction of five samples on the five-bit data patterns, the FFD performs an error-free operation within a frequency error of 7.7%. Therefore, the CDR has a robust FD-to-PD transition. By using the proposed FD, this CDR circuit not only achieves a wide frequency capture range of 43%, but also has a short frequency settling time of $680~\mu \text{s}$ . This CDR circuit is fabricated in 40-nm CMOS technology and occupies an active area of 0.1004 mm2. The total power of the receiver is 39.9mW at 16 Gb/s, and the calculated energy efficiency is 2.49pJ/b.

Ultra-wide band (O to L) photonic integrated polymer cross-bar switch matrix.

We present an ultra-wide band photonic integrated 4×4 polymer cross-bar switch matrix based on total internal reflection and the thermo-optic effect. The photonic integrated polymer switch owns low insertion loss, low power consumption, wavelength, and polarization-independent operation for all switching paths. The experimental results show ultra-wide band (O- to L-band) operation with fiber-to-fiber insertion losses ranging from -3.7 to -6.5dB, 0.1 to 0.6 dB polarization-dependent losses, switching the on-off ratio above 36 dB on average, and 25 mW power consumption per path. Error-free operation with a power penalty <0.2dB at 1 E-9 bit error rate (BER) for ultra-wide band non-return-to-zero on-off keying (NRZ-OOK) wavelength-division multiplexing (WDM) switched signals at 10, 25, 40, and 50 Gbit/s, and 510 Gbps dual polarization 64-QAM switched data with a negligible penalty were measured.

Multi-Band Photonic Integrated Wavelength Selective Switch

As fiber-optic systems turn toward multi-band transmission (MBT), exploiting the complete low loss window of optical fibers, novel optical components, able to operate in bands other than the conventional C-band, become necessary. In light of this, we report on a multi-band photonic integrated <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mathbf {1\times 2}$</tex-math></inline-formula> wavelength selective switch (WSS) operating in the O, S, C and L-bands. The photonic integrated WSS presented in this work uses a folded arrayed-waveguide grating (AWG) as the filtering element, while the wideband operation of the thermo-optic switches allows the routing of the individual channels from those bands to any of the device output ports. The operation of the WSS is experimentally validated for different bands and modulation formats. Results show error-free operation with limited penalty with intensity-modulation direct-detection (IM/DD) non-return-to-zero on-off keying (NRZ-OOK) up to 35 Gb/s in O, S, C and L-bands and up to 169.83 Gb/s with coherent 64-quadrature amplitude modulation (QAM) data transmission in the S, C and L-bands.

M-ary quadrature amplitude modulation order optimization for terahertz wireless communications over dispersive channels

Highly accurate atmospheric models, based on molecular resonance information contained within the HITRAN database, were used to simulate the propagation of high capacity single-carrier quadrature amplitude modulated signals through the atmosphere for various modulation orders. For high-bandwidth signals such as those considered in this work, group velocity dispersion caused by atmospheric gases distorts the modulated waveform, which may produce bit errors. This leads to stricter Signal-To-Noise Ratio requirements for error-free operation, and this effect is more pronounced in high-order modulation schemes. At the same time, high-order modulation schemes are more spectrally efficient, which reduces the bandwidth required to maintain a given data rate, and thus reduces the total group velocity dispersion in the link, resulting in less distortion and better performance. Our work with M-ary quadrature amplitude modulated signals shows that optimal selection of modulation order can minimize these conflicting effects, resulting in decreased error rate, and reducing the performance requirements placed on any equalizers, other dispersion-compensating technologies, or signal processing hardware.

PDM-16QAM transmission of 135 GBaud enabled by 120 GSa/s DAC and Tomlinson-Harashima pre-coding.

We experimentally verified that Tomlinson-Harashima (TH) pre-coding for an optical coherent system can enhance the speed of polarization division multiplexing (PDM) 16 quadrature amplitude modulation (QAM) signal to be higher than 135 GBaud with 120 GSa/s digital-to-analog converter (DAC) and electrical/optical/electrical bandwidth of the system narrower than 57 GHz at -30dB. The improvement of achievable capacity based on the received SNR in optical back-to-back conditions could be obviously observed by comparing the PDM-16QAM signal with and without TH pre-coding. The normalized generalized mutual information of the 135 GBaud PDM-16QAM signal for 120 km standard single mode fiber transmission was much higher than the threshold of error-free operation of a 5/6 code rate of digital video broadcasting satellite second generation low-density parity check forward error correction. To the best of our knowledge, the ratio of the symbol rate to the DAC sampling rate (135 GBaud over 120 GSa/s) is the highest ever reported for DAC-based optical coherent systems. The reachable distance of a 140 GBaud PDM-16QAM signal can be predicted to be approximately 100 km, even with the imperfect timing recovery operation.

Investigation of Timing Parameters in Single-Flux-Quantum Circuits Using Low Critical-Current Junctions and Low Bias Voltages

In this study, the trade-off among power consumptions, operating frequencies, and error rates in low-power single-flux-quantum (SFQ) circuit is investigated. The power consumption of SFQ circuits can be reduced by the lowering critical currents ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$I_{\mathrm{c}}$</tex-math></inline-formula> values) of the Josephson junctions (JJs), or the bias voltage ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$V_{\mathrm{b}}$</tex-math></inline-formula> ). The shifts and spreads of timing parameter fluctuations when <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$I_{\mathrm{c}}$</tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$V_{\mathrm{b}}$</tex-math></inline-formula> were lowered were numerically analyzed, with consideration of thermal noise at 4.2 K. The timing behaviors after <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$I_{\mathrm{c}}$</tex-math></inline-formula> was lowered were relatively simple, being based on the signal-to-noise ratio, whereas those for lowered <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$V_{\mathrm{b}}$</tex-math></inline-formula> values were complicated because of the dynamic behaviors of JJs driven at reduced voltage. The simulation results imply that the operating frequencies decreased because the timing windows narrowed, but the highest energy efficiency was obtained when we lowered <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$I_{\mathrm{c}}$</tex-math></inline-formula> or <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$V_{\mathrm{b}}$</tex-math></inline-formula> to 6.25% of their conventional values, and the energy reduction after lowering of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$V_{\mathrm{b}}$</tex-math></inline-formula> was 26% better than that after lowering of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$I_{\mathrm{c}}$</tex-math></inline-formula> . Moreover, if a small error rate (for example <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$10^{-6}$</tex-math></inline-formula> ) is acceptable, further improvement in energy efficiency would be expected at significantly higher clock frequencies than would be the case if the SFQ circuit must exhibit error-free operation.

Time Borrowing Flip-Flop architecture for error masking in near threshold voltage regime

This As dynamic delay variability increases with near-threshold voltage operation, wide timing margins need to be integrated in DVFS (Dynamic Voltage and Frequency Scaling) when deciding the frequency of operation to ensure reliable and error-free operation. Hence the maximum frequency (which is already low) in near-threshold operation is limited by these timing margins. Online methodologies for the resilience of temporal arrangement errors facilitate the recovery of temporal arrangement margins, increasing efficiency and/or energy consumption. This study presents a method for the resilience of online temporal arrangement errors that masks temporal arrangement errors by borrowing time from the phases of serial pipelines. Planned style, while not instruction replay or roll-back support, will recover temporal arrangement margins.

Rfid-Reshapes the World of Supply Chain Management

The significance of RFID for problem solving of the supply chain is underlined. RFID is an excellent element for all industries to work smoothly. The overwhelming utility of RFID technology is widely used. There is hardly a sector where we do not use RFID, whether it is manufacturing, retail, marketing and sales, shipping, etc. Each pallet, container and commodity to be manufactured, supplied and sold is defined from RFID. It ensures quite simple and error-free business operations. It allows the industry to achieve the right quality, the right price and the right time for end users. In terms of sales and customer satisfaction it gives full benefit. The paper proposes an efficient conceptual model RFID in procurement process. Furthermore, they define attributes which facilitate the choice of RFID. Finally, the section presents the problems and advantages businesses will achieve from using this application. The supply chain mechanism is carried out through various phases called supply chain stages.

Real-Time Error Detection in Nonlinear Control Systems Using Machine Learning Assisted State-Space Encoding

Successful deployment of autonomous systems in a wide range of societal applications depends on error-free operation of the underlying signal processing and control functions. Real-time error detection in nonlinear systems has mostly relied on redundancy at the component or algorithmic level causing expensive area and power overheads. This paper describes a real-time error detection methodology for nonlinear control systems for detecting sensor and actuator degradations as well as malfunctions due to soft errors in the execution of the control algorithm on a digital processor. Our approach is based on creation of a redundant check state in such a way that its value can be computed from the current states of the system as well as from a history of prior observable state values and inputs (via machine learning algorithms). By checking for consistency between the two, errors are detected with low latency. The method is demonstrated on two test case simulations - an inverted pendulum balancing problem and a sliding mode controller driven brake-by-wire (BBW) system. In addition, hardware results from error injection experiments in an ARM core representation on an FPGA and artificial sensor degradations on a self-balancing robot prove the practical feasibility of implementation.

A 52-Gb/s Sub-1-pJ/bit PAM4 Receiver in 40-nm CMOS for Low-Power Interconnects

This article presents a quarter-rate source-synchronous PAM-4 receiver for energy-efficient chip-to-module communication. A novel single-stage multiple peaking continuous-time linear equalizer (MP-CTLE) using feedback enabled multiple peaking scheme for both high-frequency equalization (HF-EQ) and low-frequency equalization (LF-EQ) is proposed to improve the BER performance and overall energy efficiency. The LF-EQ of the MP-CTLE eliminates the need for many DFE taps in SR/VSR applications to save power and area. A 1-tap feedforward equalizer (FFE) is used to further compensate for the high-frequency loss. We also use a ring oscillator based wide bandwidth phase-locked loop (WBW-PLL) as the multiphase clock generator (MPCG) in the clock and data recovery loop to save power with acceptable phase accuracy. Fabricated in 40-nm CMOS technology, the prototype receiver chip achieves error-free operation up to 52 Gb/s PAM-4 with superior bit efficiency of 0.126pJ/bit/s/dB while compensating 7.3-dB channel loss at 13GHz. With the proposed single-stage MP-CTLE, the receiver extends the error-free operation from PRBS-7 to PRBS-9. The BER bathtub curve at $10^{-6}$ is improved from 0.018 UI to around 0.1 UI.

InAs/InP Quantum Dash Semiconductor Coherent Comb Lasers and their Applications in Optical Networks

We report on the design, growth, and fabrication of InAs/InP quantum dash (QD) gain materials and their use in lasers for optical network applications. A noise performance comparison between QD and quantum well (QW) Fabry–Perot (F-P) lasers has been made. By using the QD gain material we have successfully developed and assembled C-band coherent comb laser (CCL) modules with an electrical fast feedback loop control system to ensure a targeted mode frequency spacing. The frequency spacing was maintained within ±100 ppm and the operation wavelengths locked on the desired ITU grid within 0.01 nm over a period of several months. We also investigated a 25-GHz C-band QD CCL with an external cavity self-injection feedback locking (SIFL) system to reduce the optical linewidth of each individual channel to below 200 kHz in the wavelength range from 1537.55 nm to 1545.14 nm. The RF mode beating signal 3-dB bandwidth was also reduced from 9 kHz to approximately 500 Hz with this SIFL system. These QD CCLs with ultra-low relative intensity noise (RIN), ultra-narrow optical linewidth, and ultra-low timing jitter are excellent laser sources for multi-terabit optical networks. Using a 34.2 GHz QD CCL we demonstrate 10.8 Tbit/s (16QAM 48 × 28 GBaud PDM) coherent data transmission over 100 km of standard single mode fiber (SSMF) and 5.4 Tbit/s (PAM-4 48 × 28 GBaud PDM) aggregate data transmission capacity over 25 km of SSMF with error-free operation.

1.6 Tbps Silicon Photonics Integrated Circuit and 800 Gbps Photonic Engine for Switch Co-Packaging Demonstration

We describe the performance of high bandwidth-density silicon photonic based integrated circuits (SiPh ICs) that enable the first fully functional photonic engine (PE) module co-packaged with an Ethernet switch. We demonstrate the 1.6 Tbps SiPh transmitter (Tx) IC that integrates on-die all the lasers, micro ring modulators, monitor photodetectors, spot size converters, and V-grooves that are needed to support sixteen 106.25 Gbps PAM4 optical transmit channels. This SiPh Tx, together with discrete receiver (Rx) SiPh ICs, enabled an 800 Gbps PE. The PE is designed to allow up to sixteen modules to be co-packaged around a high-bandwidth switch ASIC. The PE test results described in this article were obtained using sixteen 53.125 Gbps electrical channels that were multiplexed to drive eight simultaneously operating 106.25 Gbps optical channels. We report DR4 IEEE standards compliant high-speed optical eye performance as well as full link operation. Post-FEC error-free operation over temperature and over extended time duration is demonstrated on all channels.

56 Gb/s NRZ O-Band Hybrid BiCMOS-Silicon Photonics Receiver Using Ge/si Avalanche Photodiode

We report on hybrid BiCMOS-Silicon photonics receivers with waveguide coupled Ge/Si avalanche photodiodes, designed in a lateral separate charge absorption multiplication configuration. We demonstrate optical modulation amplitude sensitivities of -14.4 dBm for error-free operation at 50 Gb/s and -18.6 dBm under the KP4-FEC limit at 56 Gb/s using NRZ-OOK modulation. An in-depth analysis of the receiver sensitivity is carried out to understand the impact of dark current, and to identify pathways for further improvements. The demonstration of such highly sensitive receivers, supported with a receiver model, paves the way to improve optical link margins at 50 Gb/s and beyond.

Tool-Center-Point Control of a Concrete Pump Using Constrained Quadratic Optimization

Tool-center-point (TCP) control increases the operating comfort of concrete pumps by shifting the control to the task space. The operation is accompanied by various requirements and constraints from the mechanical structure, the hydraulic system, and the operator. They must be taken into account for the efficient and error-free operation of the concrete pump. In this publication, a TCP control algorithm based on constrained quadratic optimization (cQP) is presented, which addresses the requirements and constraints of a mobile concrete pump. The features include boom deformation compensation, multiple operation modes, configuration control, compliant constraints on the joint movement, and hydraulic flow rate constraints. The methods are verified by simulation for a flexible link six degrees of freedom concrete pump. The results include deformation-compensated 2-D/3-D movements of the TCP with different operation modes and configuration control under joint and hydraulic constraints. Note to Practitioners —For effective concrete placement, the tip of the concrete pump needs to move linearly in the task space. Tool-center-point (TCP) control allows the operator to directly specify the tip velocity in the task space instead of separately controlling the axes of the manipulator. In this article, the control task is posed as an inverse kinematic problem, which is solved by quadratic optimization (cQP). The framework of cQP enables the direct inclusion of system constraints while being computational efficient for online implementation on the electronic control unit of the truck. The approach addresses concrete pump specific problems and requirements of the tool center point movement and actuator constraints. Restrictions in the task space are not treated.

10 Channel WDM 80 Gbit/s/ch, 256 QAM Bi-Directional Coherent Transmission for a High Capacity Next-Generation Mobile Fronthaul

We describe the first on-line 256 QAM digital coherent optical transmission system with an ECLD light source and DFB LD-based injection-locking, and an FPGA-based transceiver. In this system, precise optical phase control was achieved with an optical injection-locking circuit and a phase-locked loop circuit at the receiver, which helped to reduce the complexity of digital signal processing in the FPGA-based receiver. The precise polarization-demultiplexing of a 256 QAM signal was realized by using a training symbol in the FPGA. With these techniques, we successfully demonstrated the on-line detection of a QAM signal with a multiplicity as high as 256. We then present a 10 channel WDM 80 Gbit/s/ch, 256 QAM bi-directional coherent transmission as a high capacity next-generation mobile fronthaul by using the FPGA-based transmission system. We achieved error-free operations with a 14% overhead FEC for 10 km down-link (on-line) and up-link (off-line) transmissions for all channels.

ПІДСИСТЕМА «ПРАЦІВНИК» У СИСТЕМІ КЕРУВАННЯ ОХОРОНОЮ ПРАЦІ НА ПІДПРИЄМСТВІ

Розглянуто теоретичні засади щодо підходів у вирішенні проблеми зменшення травматизму та покращення умов праці. Показано, що складність питання щодо забезпечення ефективного рівня безпеки працівників, вимагає застосування багатофакторних методів дослідження. Наведені результати у теоретичному досліджені довели необхідність та можливість використання теорії системного аналізу у поєднанні із теорією автоматичного керування та теорії надійності для досягнення цієї мети. Визначено, що виробничі умови праці та завдання, які висуваються керівниками до працівників, у 21 сторіччі, все більше набувають формалізованого (детермінованого) вигляду. Працівники на виробництві щодо питань безпечного поводження, повинні дотримуватись правил, які обмежують їх активність, а це накладає відбиток на їх поведінку. Доведено, що треба враховувати можливі збурення та протидію щодо виконання цих правил та обмежень. Необхідно реєструвати усі помилки та відхилення від нормального стану працівника починаючи із самих незначних. Показано, що система керування безпекою базується на ефективній та безпомилкової роботи підсистеми «працівник», яка носить ймовірнісний характер (за природою свого походження), тобто помилки можуть мати місце у роботі. Вказується на необхідність врахування усіх складових дуалістичної схеми керування СУПБЗ. Наголошується на тому, що необхідно переглянути усі інструкції з охорони праці із урахуванням ризиків не виконання вимог безпеки та з урахуванням їх наслідків. Звертається увага на те, що системи автоматичного контролю у системах автоматичного керування, повинні бути втілені на виробництві для забезпечення реєстрації безпомилкової роботи працівників, та надання їм допомоги у разі складних виробничих ситуацій.

A 50–20 Gb/s, 80 mW Photonic Receiver With 59–70 dBΩ Gain and 12.3–8.2 pA/√Hz Input-Referred Noise

This letter presents the design and measurements of a monolithically integrated photonic receiver manufactured in 0.25 μm SiGe BiCMOS electro-photonic technology. The receiver consists of an on-chip germanium photodiode directly connected to the transimpedance amplifier (TIA). An on-chip, low-noise feedback loop compensates the dc photocurrent. The circuit provides a maximum bandwidth of 35.6 GHz at a gain of 59.2 dBQ with a noise of 12.34 pA/√(Hz) while consuming only 80 mW. In combination with a 20 GHz, 1550 nm electro-optical transmitter, a maximum data rate of 50 Gb/s at a bit error rate of less than 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-12</sup> was measured. To the best of the authors' knowledge, this is the fastest error-free detected data rate reported for a monolithically integrated photonic receiver. Additionally, the feedback resistor of the TIA can be tuned via a MOSFET allowing error-free operation at 20 Gb/s with a sensitivity of only -13 dBm. In this setting the input-referred noise is only 8.16 pA/√(Hz).

Post-Processing Protocol for Physical-Layer Key Generation and Distribution in Fiber Networks

The unique and random physical-layer properties of optical fiber channels have been exploited for a simple and cost-effective secure key generation and distribution (SKGD). However, state-of-the-art SKGD approaches focused mainly on initial key extraction, while the post-processing protocol has to be explored to guarantee error-free operation, effective key generation rate (KGR) and high key secrecy. Here we propose a full post-processing protocol for SKGD in fiber networks. A lossy quantizer is optimized to achieve the trade-off between the KGR and key disagreement rate. The distributed source coding based information reconciliation is used to remove quantization errors. The privacy amplification is applied to improve the randomness and secrecy of the generated key using hashing functions. The post-processing protocol provides a SKGD solution of error-free, high randomness and high secrecy in fiber networks.