Jitter Characterization Research Articles

Overview of the production and qualification tests of the lpGBT

The Low-Power Gigabit Transceiver (lpGBT) is a radiation-tolerant ASIC used in high-energy physics experiments for multipurpose high-speed bidirectional serial links. Around 200,000 chips have been tested with a production test system capable of exercising the majority of the ASIC functionality to ensure its correct operation.Furthermore, specific individual qualification tests were carried out beyond the production tester limits, including radiation, multi-drop bus topology, inter-chip communication through different types of electrical links and characterization of jitter and stability of the recovered clocks.In this article, an overview of the production and qualification tests is given together with their results demonstrating the robustness and flexibility of the lpGBT.

Characterization of single-pulse photon energy and photon energy jitter at the Shanghai soft X-ray Free-Electron Laser

Characterization of single-pulse photon energy and photon energy jitter at the Shanghai soft X-ray Free-Electron Laser

Experimental and numerical characterization of timing jitter for short electron beams in a linear photo-injector

In modern particle accelerators involving short (few hundreds of fs or less) photon and particle beams, a crucial requirement is the arrival timing jitter and its modeling, taking into account different noise sources. This paper considers the arrival timing jitter of an electron beam measured at the SPARC_LAB photo-injector test facility (INFN-LNF, Frascati) and studies how the different jitter sources impact on the beam arrival time, considering three velocity bunching machine working points (WPs). This study includes the development of a first order mathematical model that describes the jitter contributions, the PIC code simulations for the machine WP description and experimental data acquired in a dedicated run at SPARC_LAB to benchmark both the proposed model and simulations.

Characterization of 3.2 Gbps readout in 65 nm CMOS technology

A new class of photon-counting pixel detectors allows for capturing of an image in several photon energy bins in one shot. A decreased pixel pitch and an increased number of energy bins are needed to enhance the spatial and spectral resolution of the detector. This led to new requirements for the readout systems and their bandwidths, as more data is generated for the same detection area. Fast differential serial communication enables high-speed data rates, thus providing an ideal solution to transfer large amounts of data generated by the detector’s front-end electronics. However, its implementation provides extra challenges. This work introduces a novel high-speed serial readout designed in a 65 nm CMOS technology that will be used in the future photon-counting X-ray imaging detectors. The design of the serial transmitter is presented together with the characterization of jitter and channel performance.

Timing jitter characterization of free-running dual-comb laser with sub-attosecond resolution using optical heterodyne detection.

Pulse trains emitted from dual-comb systems are designed to have low relative timing jitter, making them useful for many optical measurement techniques such as optical ranging and spectroscopy. However, the characterization of low-jitter dual-comb systems is challenging because it requires measurement techniques with high sensitivity. Motivated by this challenge, we developed a technique based on an optical heterodyne detection approach for measuring the relative timing jitter of two pulse trains. The method is suitable for dual-comb systems with essentially any repetition rate difference. Furthermore, the proposed approach allows for continuous and precise tracking of the sampling rate. To demonstrate the technique, we perform a detailed characterization of a single-mode-diode pumped Yb:CaF2 dual-comb laser from a free-running polarization-multiplexed cavity. This new laser produces 115-fs pulses at 160 MHz repetition rate, with 130 mW of average power in each comb. The detection noise floor for the relative timing jitter between the two pulse trains reaches 8.0 × 10-7 fs2/Hz (∼ 896 zs/Hz), and the relative root mean square (rms) timing jitter is 13 fs when integrating from 100Hz to 1MHz. This performance indicates that the demonstrated laser is highly compatible with practical dual-comb spectroscopy, ranging, and sampling applications. Furthermore, our results show that the relative timing noise measurement technique can characterize dual-comb systems operating in free-running mode or with finite repetition rate differences while providing a sub-attosecond resolution, which was not feasible with any other approach before.

The Jitter Measurement Ways: The Instrumentation

Jitter characterization is an essential requirement for different applications and technologies. For this reason, measurement approaches, decomposition methods and measurement instruments aimed at quantifying and analyzing jitter continue to be object of great interest both for researchers and manufacturers. Currently, various instruments are available to measure jitter, each one having specific advantages and disadvantages. To help engineers who deal with jitter measurements, this paper provides a schematic overview of the main types of instruments available on the market.

Characterization of the X-Ray Angular Pointing Jitter in the LCLS Hard X-ray Undulator Line

Characterization of the X-Ray Angular Pointing Jitter in the LCLS Hard X-ray Undulator Line

Noise and Jitter Characterization of High-Speed Interfaces in Heterogeneous Integrated Systems

Heterogeneous integration allows multiple silicon dies of various technologies and complexity to communicate efficiently using second-level interconnects, interposers, in a single package. The interposer also provides a low-impedance power delivery path between multiple independent power domains. Although the channels are very short and the signal integrity is not a challenge, the huge increase in the transient current of multiple dies and the unique clocking architecture makes the supply noise and timing jitter the limiting factors in designing high-performance multidie systems. In this article, accurate analysis and characterization techniques of noise and jitter in multidie interfaces are presented. Power supply noise and empirically derived jitter models are correlated with measurements and detailed transistor-level circuit simulations, respectively.

The jitter measurement ways: The jitter decomposition

Today, several applications and technologies require a suitable jitter characterization. For this reason, measurement methods and instruments aimed at quantifying and analyzing jitter continue to be proposed and developed by the research community and manufacturers.

An Experimental Evaluation and Characterization of VoIP Over an LTE-A Network

Mobile telecommunications are converging towards all-IP solutions. This is the case of the Long Term Evolution (LTE) technology that, having no circuit-switched bearer to support voice traffic, needs a dedicated VoIP infrastructure, which often relies on the IP Multimedia Subsystem architecture. Most telecom operators implement LTE-A, an advanced version of LTE often marketed as 4G+, which achieves data rate peaks of 300 Mbps. Yet, although such novel technology boosts the access to advanced multimedia contents and services, telco operators continue to consider the VoIP market as the major revenue for their business. In this work, the authors propose a detailed performance assessment of VoIP traffic by carrying out experimental trials across a real LTE-A environment. The experimental campaign consists of two stages. First, we characterize VoIP calls between fixed and mobile terminals, based on a dataset that includes more than 750,000 data-voice packets. We analyze quality-of-service metrics such as round-trip time (RTT) and jitter, to capture the influence of uncontrolled factors that typically appear in real-world settings. In the second stage, we further consider VoIP flows across a range of codecs, looking at the trade-offs between quality and bandwidth consumption. Moreover, we propose a statistical characterization of jitter and RTT (representing the most critical parameters), identifying the optimal approximating distribution, namely the Generalized Extreme Value (GEV). The estimation of parameters through the Maximum Likelihood criterion, leads us to reveal both the short- and long-tail behaviour for jitter and RTT, respectively.

Ultralow jitter silica microcomb

Silica microcombs have a high potential for generating tens of gigahertz of optical pulse trains with ultralow timing jitter, which is highly suitable for higher speed and higher bandwidth information systems. So far, the accurate characterization of timing jitter in microcombs has been limited by the measurement methods—although theoretically predicted to be > 20 d B better performance, the true performance has not been accurately measured until now. Here, using a self-heterodyne-based measurement method with 20 z s / H z 1 / 2 resolution, we show that 2.6-fs rms timing jitter is possible for 22-GHz silica microcombs. We identified their origins, which suggests that silica microcombs may achieve 200-as-level jitter by better intensity noise control. This jitter performance can greatly benefit many high-speed and high-bandwidth applications including analog-to-digital conversion, microwave generation, and optical communications.

极低时间抖动的飞秒激光技术（特邀）

The time jitter of a femtosecond laser is the short-term deviation of the optical pulse position relative to its ideal equally spaced pulse position. Femtosecond lasers emit uniformly spaced ultrashort pulse train. The quantum-noise-limited timing jitter can be as low as few tens of attoseconds in millisecond time scale. This unique property and its advanced applications constitute a new branch of ultrafast research, Attosecond precision ultrafast photonics. In this paper, the recent advances in femtosecond laser timing jitter research, high-precision timing jitter characterization methods, and the ultralow timing jitter that can be achieved by different kinds of femtosecond laser sources were reviewed. Finally, the application of low-jitter femtosecond lasers in the fields of synchronization of large-scale scientific instruments, high-speed analog-to-digital conversion, absolute ranging technology and coherent beam combination are introduced.

The jitter measurement ways: The jitter graphs

In recent years, jitter characterization has acquired an ever greater importance for many applications and standard technologies. As a consequence, several measurement approaches have been developed, including different jitter graphical representations, decomposition methods and measurement instruments that can be used singularly or together. Unfortunately, choosing the approach most suited to the particular need and / or specific application can be very hard. To help engineers dealing with the graph choice, this paper provides an overview of jitter graphical representations, highlighting their limitations and advantages.

Timing Jitter Characterization of the SFQ Coincidence Circuit by Optically Time-Controlled Signals From SSPDs

We report on the timing jitter characterization of the superconducting single flux quantum (SFQ) coincidence circuit, which is an essential component of the superconducting coincidence photon counter. Two superconducting nanowire single photon detectors (SSPDs), each of which is irradiated with optically time-controlled photons, are connected to the SFQ coincidence circuit, and the timing jitter of the SFQ circuit is evaluated by changing the relative time delay between two input ports for the SFQ comparator unit. We successfully observe the transition curve of the probability of obtaining the signal from the SFQ coincidence circuit by sweeping photon arrival time to each SSPD and confirm that this curve shifts temporally upon changing the bias current to the Josephson transmission line (JTL) in the SFQ circuit. A systematic investigation reveals that the relation between time delay and the bias current to JTL can be estimated. The full width half maximum timing jitter of the SFQ circuit is 1.1 ps, which is sufficiently low so that it does not influence the entire timing jitter of the coincidence photon counter.

Simulation Model to Predict BER Based on S-Parameters of High-Speed Interconnects

This work aims to predict bounds on bit-error-rate performance of highspeed interconnects. The novelty lies in the characterization of timing jitter to achieve more accurate modeling of such interconnects. —Sudeep Pasricha, Colorado State University

Minimizing attosecond CEP jitter by carrier envelope phase tuning

Minimizing the CEP jitter of isolated attosecond pulses (IAP) will be important for future applications. This jitter is experimentally and theoretically investigated and can be minimized when the driving pulse is near its Fourier limit but with slightly negative chirp. Thus, understanding and characterization of the CEP jitter of IAPs is a first step towards exact control of the electric field of IAP pulses.

Review of low timing jitter mode-locked fiber lasers and applications in dual-comb absolute distance measurement

Passively mode-locked fiber lasers emit femtosecond pulse trains with excellent short-term stability. The quantum-limited timing jitter of a free running femtosecond erbium-doped fiber laser working at room temperature is considerably below one femtosecond at high Fourier frequency. The ultrashort pulse train with ultralow timing jitter enables absolute time-of-flight measurements based on a dual-comb implementation, which is typically composed of a pair of optical frequency combs generated by femtosecond lasers. Dead-zone-free absolute distance measurement with sub-micrometer precision and kHz update rate has been routinely achieved with a dual-comb configuration, which is promising for a number of precision manufacturing applications, from large step-structure measurements prevalent in microelectronic profilometry to three coordinate measurements in large-scale aerospace manufacturing and shipbuilding. In this paper, we first review the sub-femtosecond precision timing jitter characterization methods and approaches for ultralow timing jitter mode-locked fiber laser design. Then, we provide an overview of the state-of-the-art dual-comb absolute ranging technology in terms of working principles, experimental implementations, and measurement precisions. Finally, we discuss the impact of quantum-limited timing jitter on the dual-comb ranging precision at a high update rate. The route to high-precision dual-comb range finder design based on ultralow jitter femtosecond fiber lasers is proposed.

Timing jitter of high-repetition-rate mode-locked fiber lasers.

We characterize the timing jitter of the pulse trains from 880MHz Yb-doped nonlinear polarization rotation mode-locked fiber lasers based on a balanced optical cross-correlation method. Jitter spectral density at different net-cavity dispersions has been characterized, and the near-zero dispersion shows the lowest rms timing jitter (10fs rms, integrated from 30kHz to 5MHz). The measurements have been compared with analytical models. The comparison shows that the RIN-coupled timing jitter by nonlinearity is the dominated origin of the measured timing jitter below ∼100 kHz, while amplified spontaneous emission noise makes a major contribution in the high frequency range above hundreds of kilohertz. To the best of our knowledge, this is the first high-precision timing jitter characterization for the ∼gigahertz level repetition rate mode-locked fiber lasers. The results will be of great importance for further improving the laser performance for many applications.

Pile-up correction in characterizing single-photon avalanche diodes of high dark count rate

Although as a single-photon detector, the single-photon avalanche diode (SPAD) may be applied to multi-photon conditions. At a minimum, SPADs with a high dark count rate (DCR) demand a higher value of photon number per pulse to improve the signal-to-noise ratio. In this case, and without correction, severe pile-up distortion may induce a system error in the measurement of photon detection efficiency (PDE) and timing jitter. In this paper, we study the pile-up distortion in SPAD characterization by numerical simulation and experimentation, and introduce a pile-up correction method for the precise characterization of PDE and timing jitter in immature SPADs with an unintentionally high DCR. The results of this study are useful in the development of future SPADs.

F93. Probabilistic jitter characterization

Introduction Bayesian probabilistic characterization has already been used for quantitative electromyography but not for jitter analysis. Instead of classical statistical method, probabilistic characterization uses sequential cumulative probability. Our objective was to evaluate the performance of probabilistic characterization for jitter assessment. Methods We analyzed 20 controls and 20 patients with serologically confirmed Myasthenia Gravis (MG). All patients were submitted to orbicularis oculi concentric needle voluntary jitter measurements of 20 pairs of ASFAP, adding up 797 MCD measurements. Jitter was characterized in four different levels: A: μ s; B: 25–45 μ s; C: 45–65 μ s; and D: >65 μ s. We calculated the probability of an abnormal result for each jitter level. Then, we used the Bayesian sequential approach in each subject until the cumulative probability of a normal or abnormal result was >99%. Results The probability of abnormality for each jitter level was: A: 20%; B: 73%; C: 95%; and D: 99%. The cumulative probability achieved more than 99% up to the sixth potential in 77% of the subjects. However, one control subject was labeled as abnormal while four MG subjects were labeled as normal studies. Additionally, two control subjects could not be characterized up to the 20th recording. The method accuracy was 82%. Conclusion Probabilistic characterization requires fewer recordings than the statistical method. However, our study showed poor accuracy for jitter characterization. One possible reason is that MCD values in each patient are not randomly scattered during the entire exam, but rather clustered according to the sampled region.