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This paper reviews a statistical signal integrity (SI) analysis at the system level for a high-speed system design. An eye diagram graphically shows a system's performance. However, an eye diagram requires a long acquisition time for accurate results. The time-consuming nature of this process makes an eye-diagram-based SI analysis inefficient. Thus, a statistical eye diagram was introduced for an efficient SI analysis. The statistical eye diagram provides not only SI metrics such as eye height (EH) and eye width (EW), but also the bit-error rate (BER) profile for each channel. The data transmitted over the high-speed channels are determined by an upper hierarchy such as a system. In other words, the data are a function of the system parameters. In conclusion, a statistical eye diagram is determined by the high-speed channels and the system parameters. Therefore, the previous works on statistical eye diagrams at the channel and system levels have been introduced, respectively. This paper reviews the previous works for a system-level statistical SI analysis with a statistical eye diagram. [ABSTRACT FROM AUTHOR]

Summary: In this article, we investigated a new structure of a protective meander line (ML): a meander microstrip line (MSL) with two passive conductors. The existing theory of ultra‐short pulse (USP) attenuation in MLs is presented for the first time. Based on this theory, we determined the number of decomposed pulses at the output of the MSL line with two passive conductors, and, for the first time, formulated the conditions for pulse decomposition in the line. The folding of the MSL line into non‐core turns was studied in detail. As a result of this article, we proposed a new theory that involves the utilization of additional groups of decomposed pulses for enhanced USP attenuation. These additional groups were thoroughly examined, and the delays of pulses from these groups were defined. This analysis allowed identifying the reason for their appearance. It was revealed that folding the ML into non‐core turns allows further attenuation of the USP amplitude, which increases with the increase of the number of non‐core turns. To validate the obtained simulation results, we performed experimental measurements and obtained good consistency of the results. The N‐norms analysis demonstrated that the combined use of such folding and passive conductors reduces the probability of electrical breakdown, arc discharge, and dielectric breakdown. The maximum USP attenuation at the output was 24.9 dB. As a result of useful signal integrity analysis, it is proposed to use a folded MSL together with a USB 2.0 "Full‐speed" interface with a data transfer rate of 12 Mbit/s. In addition, it is proposed to use such MSLs in DC power circuits. [ABSTRACT FROM AUTHOR]

With the exponential growth in information related applications and the continuous increase in voice over IP (VoIP) applications, the carriers are expanding their networks to provide improved services to their end users. In such cases, the synchronous optical network/synchronous digital hierarchy model is not suitable. In this work, we are going to investigate the electro optic switch with the help of a VB script to simulate the device for various parameters. Further, we will then scan the central electrode voltages and take account of the overlap integral taking place at the output port with the help of waveguide mode. The best switching for switches at different voltages so as to have negligible coupling loss for different input signals is investigated. We aim to evaluate the MZI switches with the Li-Tn channel profile wave guiding structure and confirm their performance as compared to the existing MZI switches. [ABSTRACT FROM AUTHOR]

Free space optical (FSO) communication reduces the last-mile bottleneck problem wherever we cannot use fiber-optic links. Performance degradation in the FSO system is mainly due to the atmospheric turbulence effect. To increase the capacity of the system wavelength division multiplexing (WDM) is used. An experimental testbed is set up to investigate the performance of the DWDM-FSO system with and without crosstalk under the influence of atmospheric turbulence. For the study of the system performance, the attenuation values due to scintillation from the existing work are taken as losses. Based on the results, the FSO link length that supports the data transmission is up to 3 km for the tolerable BER of 10−9. The Q-factor value drops with increasing attenuation and link distance. Q value of the FSO system without crosstalk and with crosstalk at 2 dB is 10.64 and 6.34 for 1 km and 4 km, it is 7.94 and 4.24 respectively. [ABSTRACT FROM AUTHOR]

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The design level of channel physical characteristics has a crucial influence on the transmission quality of high-speed serial links. However, channel design requires a complex simulation and verification process. In this paper, a cascade neural network model constructed of a Deep Neural Network (DNN) and a Transformer is proposed. This model takes physical features as inputs and imports a Single-Bit Response (SBR) as a connection, which is enhanced through predicting frequency characteristics and equalizer parameters. At the same time, signal integrity (SI) analysis and link optimization are achieved by predicting eye diagrams and channel operating margins (COMs). Additionally, Bayesian optimization based on the Gaussian process (GP) is employed for hyperparameter optimization (HPO). The results show that the DNN–Transformer cascaded model achieves high-precision predictions of multiple metrics in performance prediction and optimization, and the maximum relative error of the test-set results is less than 2% under the equalizer architecture of a 3-taps TX FFE, an RX CTLE with dual DC gain, and a 12-taps RX DFE, which is more powerful than other deep learning models in terms of prediction ability. [ABSTRACT FROM AUTHOR]

Fibreless optics or free space optical communications (FSOC) has been at the forefront of many academic research in telecommunications due to its numerous benefits of large spectrum, high-speed data transmission, security, low transmit power, unlicensed spectrum and non-interfering links. Among the technical challenges of dense deployment of small cells in heterogeneous networks (HetNet) is a flexible and cost-effective backhaul link. This paper proposes, designs, simulates and evaluates the performance of a 350 m FSOC link under different atmospheric impairments for picocell to macrocell backhauling applications. The performance of the FSOC link is assessed by evaluating bit error rate (BER), eye diagram and quality factor (Q-factor). Results obtained recommend the FSOC link deployment for picomacrocell backhauling under the weather conditions of clear sky with/without turbulence, heavy rain, heavy haze, heavy fog and wet snow. [ABSTRACT FROM AUTHOR]

The energy of electromagnetic radiation from explosions is coupled to electronic equipment circuits, disrupting the initiation sequence or causing failure in an increasing number of cases, which seriously affects the stability of weapon systems. There is a significant difference between the characteristics of the explosive electromagnetic radiation signals and modulated electromagnetic signals. The electric field intensity and signal power cannot directly represent the magnitude of the explosive electromagnetic radiation energy, and traditional electromagnetic signal analysis methods are unsuitable for explosion electromagnetic signal analysis. To solve this problem, the mechanism of explosive electromagnetic radiation was first analyzed. Through verification experiments of the explosion electromagnetic intensity and temperature, it was concluded that there is a strong correlation between the explosion plasma temperature and electromagnetic intensity. The temperature of the explosive plasma is derived based on the measured surface temperature of the explosive fireball, a functional relationship is established between the energy of the explosive plasma and the temperature of the plasma, and plasma energy is introduced as a parameter for electric field intensity correction. The interference signal analysis method based on eye diagram is used to calibrate the electromagnetic radiation damage ability, achieving quantitative analysis of the interference degree of electromagnetic radiation energy on the signal, and providing a new approach for the analysis of explosive electromagnetic radiation energy. [ABSTRACT FROM AUTHOR]

In optical communication systems, the Q-factor is an important performance metric to evaluate the performance of an optical link. In this paper, a deep learning-based eye diagram analyzer is proposed to estimate the Q-factor. CNN architectures such as LeNet, Wide ResNet, and Inception-v4 are used for ON-Off Keying (OOK) and Pulse Amplitude Modulation (PAM) formats’ eye diagrams. The performance of these architectures is evaluated in terms of accuracy, Mean Squared Error (MSE), and error tolerance. This work shows that Wide ResNet demonstrates better performance in both OOK and PAM4 transmission schemes, achieving MSE values of 0.00188 and 0.00036, respectively. Additionally, it attains a high R-squared (R2) value of 0.9998. This deep learning-based eye diagram analyzer may be a promising approach for analyzing and optimizing optical communication systems without extensive human intervention.

This paper introduces a new simple moment-generating function (MGF) design modelling method to conclude an optimum filter to maximize the Q-factor and increase the link communication span. This approach mitigates the pulse temporal dispersion, particularly the underwater wireless optical communication (UWOC) systems. Hence, some form of equalizing filter design is highly desirable. The model solution environment includes a Double Gamma Function (DGF) water channel impulse response, intersymbol interference (ISI), stochastic Poisson process, and additive Gaussian thermal noise (AGTN). The optimal filters exhibit temporal profiles comparable to those derived by published works based on complex Chernoff Bound (CB) and Modified Chernoff Bound (MCB) methods. The results show the impact of the optimum filter at a signal level and optical receiver level utilizing Eye-Diagrams and BER vs. Q-Factor, respectively. The computation involves four different UWOC propagation channel models for Coastal and Harbor waters. One of the main conclusions indicates that the optimum filter manages the temporal dispersion due to the ISI impairment correctly. Also, the proposed optimum filter reduces eye-opening and the corresponding Q-Factor by less than 15% for a five-times increase in pulse width for the same transmitted optical power level. [ABSTRACT FROM AUTHOR]

Purpose: The design, fabrication and experimental validation of defected microstrip structure (DMS) are proposed to address the problem of near-end crosstalk (NEXT) and far-end crosstalk (FEXT) between the microstrip transmission lines in a printed circuit board. Design/methodology/approach: The proposed DMS evolved with the combination of spur line (L-shaped DMS) and U-shaped DMS topologies. This technique reduces the strength of electromagnetic coupling and suppresses crosstalk by optimizing the capacitive and inductive coupling ratio between the linked microstrip lines. The practical inductance value is much more significant in DMS than in defected ground structures (DGS), but the capacitance value remains the same. Findings: A DMS unit is etched on the aggressor microstrip line instead of the DGS circuit. Because there is no leakage via the ground plane and the circuit size is far smaller than with DGS, the enclosure issue is disregarded. DMS structures have a larger effective inductance and are resistant to electromagnetic interference. A tightly coupled transmission line structure with minimal separation between the coupled microstrip line is designed using DMS. Further research must be conducted to improve the NEXT, FEXT and spacing between the transmission lines. Originality/value: Simulation and actual measurement results show that the proposed DMS structure can effectively suppress crosstalk by analysing the S-parameters, namely, S_12, S_13 and S_14, with measured values of 1.48 dB, 20.65 dB and 21.099 dB, respectively. The data rate is measured to be 1.34 Gbps as per the eye diagram characterization. The results show that the NEXT and FEXT are reduced by approximately 20 dB in the frequency range of 1–11 GHz for mixed signals. The substantial measured results in the vector network analyser coincide with the computer simulation technology microwave studio suite simulation results. [ABSTRACT FROM AUTHOR]

We optimized and fabricated an ultra-bend-resistant 4-core simplex cable (SXC) employing 4-core multicore fiber (MCF) suitable for short-reach dense spatial division multiplexing (DSDM) optical transmission in the O-band. The characteristics of transmission loss, macro-bending and cross-talk (XT) between adjacent cores after cabling were firstly clarified. By introducing the trapezoid index and optimizing the cabling process, the maximum values of added XT of 1.17 dB/km due to 10 loops with a bending radius of 6 mm imposed over the 4-core SXC and a macro-bending loss of 0.37 dB/10 turns were, respectively, achieved.P Then, the optical transmission with low bit error rate (BER) was presented using a 100GBASE-LR4 transceiver over the 1.2 km long 4-core SXC. The excellent bending resistance of the 4-core SXC may pave the way for a reduction in space pressure and increase in access density on short-reach optical interconnect (OI) based on DSDM. [ABSTRACT FROM AUTHOR]

With the rapid increase in size and frame rate of TV products, high‐ speed data transmission has become a major issue to be solved. This paper studied the PCB impact factors of high‐speed digital signal transmission on large‐sized display panels, like channel loss, crosstalk between adjacent signals, etc. Simultaneously, improvement methods for signal amplitude attenuation in panel transmission systems was proposed. Based on 98' 4K 120Hz TV product platform, the signal attenuation of transmission system was evaluated, and the effectiveness of the improvement schemes also was verified, the result shows signal quality in system can be improved above 20%. [ABSTRACT FROM AUTHOR]

Using dual polarization multiplexing alternate mark inversion (AMI) downlink signals, a novel radio over fiber (RoF) system integrating optical fiber and FSO channel is designed to adapt to applications in mountainous areas and other complex terrain areas. Optical heterodyne technology and self-mixing homodyne detection method are used to realize high sensitivity detection of the received signals after 25.1 km channel (including 1 km single-mode fiber and 100 m free space link) transmission. Moreover, polarization multiplexing technology is introduced to exponentially increase the transmission capacity of downlink signals. This scheme not only can be compatible with traditional optical fiber transmission systems, but also support the wireless optical access application of millimeter wave signals in RoF systems.

This paper presents several conclusions based on time domain analysis of the simulation results of several transmission lines that use frequency-dependent dielectrics, highlighting the fiberglass effect on performance. The matching conditions of the circuit are checked based on a Smith chart simulation that represents the magnitude of the reflection coefficient via scattering parameters. A time domain analysis is provided by means of the eye diagram, which allows the study of the rise and fall time, jitter, and eye height and width of the two materials considered to be appropriate for the examination of composite substrates: one conventional substrate, FR4, and one more oriented to high-speed design constraints, N4000-13. Time domain analyses highlight the effect of increasing the rate for our purpose on the composite substrate for coupled or single-ended interconnections or routes on PCBs. [ABSTRACT FROM AUTHOR]

This research paper presents a novel high bit rate and spectral efficient 20 Gb/s mode division multiplexed (MDM) radio over free space optical communication (MDM-RoFSO) system. 10 Gb/s MZM/QAM-16-modulated data streams, each from two distinct channels, are transported over two spiral-phased Hermite–Gaussian (HG) laser modes, HG00 and HG01, respectively. These two HG channels are multiplexed using MDM at a 10 GHz RF signal, amplified and transmitted over the atmospheric link at an optical wavelength of 1550 nm. The proposed MDM-RoFSO system is simulated for MZM modulation over two distinct HG modes in clear sky, dense haze, dense fog, and strong rain weather conditions. The performance of the system is evaluated using performance metrics such as BER, eye diagram, Q factor, and link transmission range. The simulation results show that the HG00 mode is more robust and the extended transmission range is achieved from (7 to 24.4) km for (24.4 to 2.98) Q factor for clear sky to strong rain conditions. This transmission range is further extended by the factor of (2.9 to 1.7) km when the QAM-16 modulation is incorporated in composite (HG00 + HG01) mode and then transmitted in similar weather conditions for the acceptable BER of < 10–5. Finally, the simulation results confirm that the QAM-16 modulated composite HG mode is able to mitigate the atmospheric weather conditions and travel a longer transmission distance compared to individual HG mode transmission. [ABSTRACT FROM AUTHOR]

In this paper, a technique for optical performance monitoring (OPM) using deep learning-based artificial neural network (ANN) is implemented. ANN is trained with parameters derived from eye-diagram for the identification of optical signal to noise ratio (OSNR), chromatic dispersion (CD) and polarisation mode dispersion (PMD) simultaneously and independently in a 10 Gb/s system with non-return-to-zero (NRZ) on-off keying (OOK) data signal. ANN-based OPM confirms that the proposed approach can provide reliable estimated results. The mean squared errors for OSNR, CD and differential group delay (DGD) are found to be 4.6071 dB, 0.0417 ps/nm/km and 0.0016 ps/km, respectively. The proposed technique may be utilized in analyzing the signals of future heterogeneous optical communication networks intelligently. [ABSTRACT FROM AUTHOR]

Incoherent addition of three monochromatic laser sources is used to create four distinctive power levels to match the profile of standard quaternary pulse amplitude modulation (PAM4). The proposed PAM4 signal generation results in a lower symbol error rate as compared to standard PAM4 systems. This design improves the signal-to-noise ratio as compared to existing PAM4 schemes and can reduce the cost and power consumption of existing 200 G or higher optical transceivers. [ABSTRACT FROM AUTHOR]

Free-space optical (FSO) communication is a wireless optical data transmission technology with a high data transmission rate. It has received much attention in recent years as it is cost-effective and has license free operation. It is line of sight free-space communication technique where optical signal severely degraded from atmospheric losses especially due to weather conditions; hence it restricts the link range and data carrying capacity. Therefore, a 16-channel ultra-dense wavelength division multiplexing–free space optics (UWDM–FSO) system each having each 10 Gb/s data rate is proposed to enhance the capacity and performance of FSO system. To authenticate the performance of the proposed system, investigation for different modulation formats such as nonreturn to zero (NRZ), return to zero (RZ), carrier suppressed return to zero (CSRZ) and duo binary (DB) are reported. Further, to reduce the atmospheric interference, multiple input multiple output (MIMO) technique is integrated into the proposed system. The outcomes of MIMO–UWDM–FSO link revealed a significant improvement in the bit error rate (BER), eye diagram and Q-factor, under different weather conditions. It is also observed that NRZ modulation formats perform better than RZ, CSRZ and DB formats. [ABSTRACT FROM AUTHOR]

The purpose of this study is to evaluate the impact of the location of the Er3+/Yb3+optical amplifier (EYDWA) in passive optical access network downstream (as a post-amplifier or booster, in the middle) and upstream transmission. This can give us an extended connection and a huge distribution ratio for a beneficial implementation of the optical fiber. The transmission quality was compared on the location of the amplifier as well as the length of the link. According to the results obtained by system simulation one noted that there is a clear improvement of the system performance by the effect of the amplifier (EYDWA). One could obtain a distance of more than 200 km for GPON. Moreover by varying the opto-geometric parameters such as concentration of Ytterbium ions and the length of the guide allowed us to improve the quality factor and binary error rate. [ABSTRACT FROM AUTHOR]

This work is focused to carry out the investigation of wavelength division multiplexing (WDM) approach on free space optical (FSO) transmission systems using Erbium Ytterbium Doped Waveguide Amplifier (EYDWA) integrated as post-or pre-amplifier for extending the reach to 30 Km for the cost-effective implementation of FSO system considering weather conditions. Furthermore, the performance of proposed FSO-wavelength division multiplexing (WDM) system is also evaluated on the effect of varying the FSO range and results are reported in terms of Q factor, BER, and eye diagrams. It has been found that, under clear rain the post-amplification was performed and was able to reach transmission distance over 27 Km, whereas, the FSO distance has been limited at 19.5 Km by using pre-amplification. [ABSTRACT FROM AUTHOR]

The growth of optical technology is currently being studied extensively to meet the significant demand for bandwidth. The passive optical network (PON) solves the problem of bandwidth as it extends the optical network to individuals and businesses [Sifta R, Munster P, Krajsa O, Filka M, "Simulation of bidirectional traffic in WDM-PON networks", Brno University of Technology, ISSN 0033–2097, R. 90 NR 1/2014.]. In this paper, a comparative study is made between the WDM PON system and the CWDM PON system using two different architectures, one for the WDM PON and the other for the CWDM PON, to illustrate the appropriate technique for the PON network by increasing the Q factor and the OSNR ratio while minimizing the bit error rate (BER < 10–9). Both systems are simulated at 10 Gbps for four users of bidirectional SMF (Single Mode Fiber) fiber lengths and different powers. In order to determine the transmission performance for both systems, the link was designed for fiber lengths of 20, 30, 40, 50 and 60 km as well as for powers from −10 dBm up to 10 dBm for four users. The use of the EDFA amplifier in the WDM PON system is required in this document to minimize degradation caused by attenuation [Parkirti RDK, Singh R. Cost-efficient Colorless WDM-PON Based on RSOA for High Capacity. Int J Adv Res Comput Eng Technol (IJARCET). 2016;5]. On the contrary, in the CWDM PON system, the amplification is not essential because the wavelengths used in this system are not affected by the water peak which causes a strong attenuation of the wavelengths in the 1370–1410 nm range on optical fibers [Nazir M, Arshad F, Asif R. Design and evaluation of power budget for a bidirectional CWDM-Passive Optical Network. In: International Conference on Communication, Computing and Digital Systems (C-CODE), Islamabad, Pakistan, 04 May 2017.]. The peak of water vapor absorption is close to 1383 nm. [ABSTRACT FROM AUTHOR]

On‐chip integration of two‐dimensional (2D) materials holds immense potential for novel optoelectronic devices across diverse photonic platforms. In particular, indium selenide (InSe) is a very promising 2D material due to its ultra‐high carrier mobility and outstanding photoresponsivity. Herein, a high‐speed photodetector based on a multilayer 90 nm thick InSe integrated on a silicon nitride (SiN) waveguide is reported. The device exhibits a remarkable low dark current density of ≈40 nA μm−2, a photoresponsivity of 0.38 A W−1, and an external quantum efficiency of ≈48.4%. Tested under ambient conditions at near‐infrared 976 nm wavelength, it exhibits an absorption coefficient of 0.11 dB μm−1. Additionally, the photodetector demonstrates a 3‐dB radiofrequency bandwidth of 85 MHz and an open‐eye diagram at data transmission of 1 Gbit s−1. Based on these exceptional optoelectronic advantages, integrated multilayer InSe enables the realization of active photonic devices for a range of applications, such as short‐reach optical interconnects, LiDAR imaging, and biosensing. [ABSTRACT FROM AUTHOR]

On‐chip integration of two‐dimensional (2D) materials holds immense potential for novel optoelectronic devices across diverse photonic platforms. In particular, indium selenide (InSe) is a very promising 2D material due to its ultra‐high carrier mobility and outstanding photoresponsivity. Herein, a high‐speed photodetector based on a multilayer 90 nm thick InSe integrated on a silicon nitride (SiN) waveguide is reported. The device exhibits a remarkable low dark current density of ≈40 nA μm−2, a photoresponsivity of 0.38 A W−1, and an external quantum efficiency of ≈48.4%. Tested under ambient conditions at near‐infrared 976 nm wavelength, it exhibits an absorption coefficient of 0.11 dB μm−1. Additionally, the photodetector demonstrates a 3‐dB radiofrequency bandwidth of 85 MHz and an open‐eye diagram at data transmission of 1 Gbit s−1. Based on these exceptional optoelectronic advantages, integrated multilayer InSe enables the realization of active photonic devices for a range of applications, such as short‐reach optical interconnects, LiDAR imaging, and biosensing.

The performance of an optical fiber communication system is greatly affected by various nonlinear effects. If the transmitted power level is high or the bit rate exceeds 10Gbps value, nonlinear effects become important and must be considered. The impact of different nonlinear mechanism on signal fidelity includes shifting of power between wavelength channels and decrease in signal strength. In multichannel WDM/ DWDM networks the nonlinear effects can be especially troublesome . In this paper the power loss due to nonlinear inelastic process like stimulated Raman scattering has been discussed elaborately for different high speed data transmission systems. The required mathematical model and simulation layout to determine the parametric values of fiber nonlinearities and Raman induced power penalty have been developed using MATLAB software and Opti.System simulation tool respectively. [ABSTRACT FROM AUTHOR]

Ge/Si separate absorption, charge, and multiplication avalanche photodiodes (SACM APDs) coupled with waveguides have shown significant potential as high-sensitivity, low-noise, and high-speed photodetectors for optical communications. In this study, we present a waveguide-integrated Ge/Si SACM APD fabricated on an eight-inch silicon photonics platform. The device exhibits a primary responsivity of 0.68 A/W at the unit gain voltage of 6 V for the O-band (1310 nm) wavelength, with a 10 μm-long and 1 μm-wide Ge layer. Additionally, the device demonstrates a 3 dB bandwidth of 25.7 GHz, with an input optical power of −16.8 dBm. The largest gain bandwidth product (GBP) is 247 GHz at a gain of 9.64 and a bias voltage of 15.7 V. The eye diagram is open at the bias voltage of 16 V, with a capacity to receive 28 Gbps of data. This APD shows potential for application in high-speed data transmission systems. [ABSTRACT FROM AUTHOR]

Application of fiber Bragg grating (FBG) in optical communication is an evolving field. In this research paper, various types of chirped FBG's (CFBG) have been used with avalanche photodiode (APD) on the designed optical fiber communication (OFC) link. Data rate of 20 Gbps and return-to-zero modulation format has been kept as fixed parameters. The designed link has been evaluated for varying fiber lengths (100, 200, 300, 400 and 500 km), various type of CFBG's (linear, quadratic, square root and cubic root) with Gaussian apodization function, varying grating lengths (10, 20, 30, 40 and 50 mm) and operating temperatures (5°C, 10°C, 15°C, 20°C, 25°C, 30°C). The designed OFC link has also been evaluated for APD with and without CFBG. The performance evaluation matrix parameters selected are Q-factor, bit error rate and eye diagram. The OFC link employing CFBG with APD has been found to be superior. In compensating chromatic dispersion, optimum results have been observed for linear CFBG with Gaussian apodization function in comparison to other types of CFBG with 50 mm grating length for the maximum transmission distance. [ABSTRACT FROM AUTHOR]

This article proposes a statistical shmoo for a Decision Feedback Equalizer (DFE). A statistical shmoo shows a Bit-Error Rate (BER) distribution of a system depending on conditions such as a threshold voltage and sampling time. The previous statistical eye diagram can be converted to a statistical shmoo except for the case of a DFE. In the shmoo, rows and columns represent different threshold voltages and sampling times, respectively. Thus, the DFE operation also depends on each row and column. Furthermore, a DFE may have error propagations because of substantial noise. Therefore, this article proposes a statistical shmoo for an ideal and a nonideal DFE. The ideal DFE always makes a correct bit decision, whereas the nonideal DFE may make a wrong bit decision depending on the received waveform. For verification, the obtained statistical shmoo is compared to the transient simulation with their BER values. The lowest BER value achieved by the proposed method is 1E-51 with a calculation time of 862 seconds. While the transient simulation achieved the BER of 8.26E-8 with a simulation time of 2,000,000 seconds. In conclusion, the proposed method provides an accurate statistical shmoo in efficient manner.

This article proposes an accelerated statistical eye diagram estimation method for efficient signal integrity (SI) analysis. An eye diagram is a critical metric in the SI analysis, however obtaining an eye diagram is time-consuming in simulation. The required time might be a few weeks depending on the complexity. Because the eye diagram is obtained by superposition of the received waveforms. Statistical eye diagram estimation methods were proposed to make the eye diagram acquisition efficient, however, it still has a limited improvement due to a large number of convolution operations. To address this limitation, the proposed method includes two approaches: ( $i$ ) an increased voltage step in the amplitude PDF with a compensation factor and (ii) skippable and replaceable convolution operations. The efficiency of the proposed method is verified by comparing the derived result with that of a conventional transient simulation. The previous estimation method requires 1,065 s while approaches ( $i$ ) and (ii) reduce the required time to 88 and 510 s, respectively. When both approaches are applied, the required time is reduced to 17 s in comparison to the simulation time of 259,200 s required for a transient simulation. Approach (ii) reduces the number of convolution operations from 768,000 to 103,000. Therefore, the proposed method successfully reduces the required simulation time and the required number of convolutions to obtain a statistical eye diagram.

Radio over fiber system is an integral part of the 5-Generation technology which has undergone enormous changes in the last decade. This work presents a new model for the fronthaul ROF system based on the (VSCEL) as an alternative to the classical CW laser, making use of its interesting properties, that includes narrow bandwidth and high directionality generated optical beam the influences of the bias current value of the VCSEL along with channel dispersion compensation fiber, fiber Bragg grating (FBG) and optical amplifier on the proposed system performance measures like quality factor (Q), bit error rate (BER), eye diagram and optical signal-to-noise ratio (OSNR) have been studied. The simulation results showed that the proposed model can support data transmission of 5Gbps up to 200 km with a Q-factor of around 6, in the case of using dispersion compensation fiber (DCF), along with bias current of about 5 mA. The FBG compensator gave a comparable result to that of the DCF for a transmission distance of no more than 30 km. The maximum bit rate supported by the proposed system to maintain sufficient Q-factor of about 6 was found to be 10Gbps. Furthermore, it was observed that a log (BER) gain of 89, corresponding to the received power, has been achieved in comparison with those reported in a peer model in the literature. Eventually a fair comparison has been made between the proposed system and up to date peer publications which proved the superiority of the presented system model. [ABSTRACT FROM AUTHOR]

This paper introduces a new simple moment-generating function (MGF) design modelling method to conclude an optimum filter to maximize the Q-factor and increase the link communication span. This approach mitigates the pulse temporal dispersion, particularly the underwater wireless optical communication (UWOC) systems. Hence, some form of equalizing filter design is highly desirable. The model solution environment includes a Double Gamma Function (DGF) water channel impulse response, intersymbol interference (ISI), stochastic Poisson process, and additive Gaussian thermal noise (AGTN). The optimal filters exhibit temporal profiles comparable to those derived by published works based on complex Chernoff Bound (CB) and Modified Chernoff Bound (MCB) methods. The results show the impact of the optimum filter at a signal level and optical receiver level utilizing Eye-Diagrams and BER vs. Q-Factor, respectively. The computation involves four different UWOC propagation channel models for Coastal and Harbor waters. One of the main conclusions indicates that the optimum filter manages the temporal dispersion due to the ISI impairment correctly. Also, the proposed optimum filter reduces eye-opening and the corresponding Q-Factor by less than 15% for a five-times increase in pulse width for the same transmitted optical power level.

We optimized and fabricated an ultra-bend-resistant 4-core simplex cable (SXC) employing 4-core multicore fiber (MCF) suitable for short-reach dense spatial division multiplexing (DSDM) optical transmission in the O-band. The characteristics of transmission loss, macro-bending and cross-talk (XT) between adjacent cores after cabling were firstly clarified. By introducing the trapezoid index and optimizing the cabling process, the maximum values of added XT of 1.17 dB/km due to 10 loops with a bending radius of 6 mm imposed over the 4-core SXC and a macro-bending loss of 0.37 dB/10 turns were, respectively, achieved.P Then, the optical transmission with low bit error rate (BER) was presented using a 100GBASE-LR4 transceiver over the 1.2 km long 4-core SXC. The excellent bending resistance of the 4-core SXC may pave the way for a reduction in space pressure and increase in access density on short-reach optical interconnect (OI) based on DSDM.

Abstract This study conducts comprehensive performance analyses of a commercial photonic-crystal surface-emitting laser (PCSEL) via small-signal measurement and the bit-error-rate test. Meanwhile, the radio frequency characteristics of the PCSEL are unveiled for the first time. Compared to the vertical-cavity surface-emitting lasers, the PCSEL shows great potential for a broader optical bandwidth that is benefited from the high optical-confinement factor. A maximum bandwidth of around 2.32 GHz is experimentally observed when the PCSEL was biased at 340 mA. Moreover, a theoretical calculation was applied to shed light on the characteristics of the small-signal measurement, providing a deep insight into the corresponding intrinsic response model. The signal transmission capability of the PCSEL was investigated as well. The maximum bit rate and corresponding rise time transmitted at 500 Mbps are 1.2 Gbps and 186.16 ps, respectively. Thus, a high-speed PCSEL can be realised with a shrunk form factor, serving as a promising candidate for the next-generation light sources in high-speed optical communication.

Featured Application: The proposed real-time eye diagram monitoring method has potential applications in modern optical communications and cloud computations. A real-time eye diagram monitoring method for optical signals is proposed and experimentally demonstrated based on optical sampling. In the system, the optical signals under test are directly sampled by an optical sampling pulse train with a narrow pulse width and a high repetition frequency. The sampling pulse train is achieved in a Mach-Zehnder modulator (MZM), gated on-off by an electrical pulse. The sampled optical signals are then broadened and detected by a photodetector (PD). A low-speed electrical analog-to-digital converter (ADC) will then quantify the detected electrical signals. Combining with an algorithm based on the infinitesimal calculus, the quantified data is then used to achieve the eye diagram, according to which more time-domain parameters, such as period, time jitter, Q value, and bit error rate (BER) for the optical signals under test, are obtained. Thanks to the high repetition rate of the optical sampling pulse train, the eye diagram and the time-domain parameters of the optical signals are observed in real time. Experimental results show that a real time of about 350-μs eye diagram monitoring for a 2.5-Gb/s optical signal with a dynamic range from −10 to −22 dBm is achieved. In addition, time jitters are measured to range from 4.3 to 49.8 ps. Q values are estimated to range from 20.4 to 4.3, corresponding to BERs ranging from 2.3 × 10−92 to 8.5 × 10−6. The results are also verified by a commercial real-time oscilloscope. [ABSTRACT FROM AUTHOR]

In this article, an analytic approach is proposed for estimation of oscillating signal jitter and eye diagram on a transmission line (TL). Basically, the jitter is a result of oscillator phase noise. There are two types of internal and external sources of phase noise which both are considered in the proposed stochastic estimation. Crosstalk between adjacent TLs is the main source of external phase noise on an oscillating signal of a system layout. This phenomenon on the victim TL is studied with stochastic input signal driving for the aggressor TL. For mathematical derivation, the skin effect of the TL is considered for better accuracy. The skin effect of the TL is considerable in high frequency like bit rate one. In addition, a magnetic near-field probe and test procedure are designed and proposed for the measurement of the TL operating stochastic signal without loading effect. A test board is designed and fabricated for verification of the proposed approach. The analytic derivations have good accuracy in estimation of bit rate of the TL less than 4% for the fabricated test board. For this test board, the crosstalk effect on the TL closes the eye diagram height by 30% in 20 GHz. • An analytic approach is proposed for estimation of oscillating signal jitter and eye diagram. • A closed form formal is derived for estimation of a transmission line bit rate. • The skin effect of transmission line is considered in bit rate estimation. • Internal phase noise and external stochastic crosstalk induction (aggressor line with random input signal) are accounted in jitter estimation. • A magnetic near field probe and test procedure is proposed for measurement of transmission line operating stochastic signal without loading effect. [ABSTRACT FROM AUTHOR]

This paper presents several conclusions based on time domain analysis of the simulation results of several transmission lines that use frequency-dependent dielectrics, highlighting the fiberglass effect on performance. The matching conditions of the circuit are checked based on a Smith chart simulation that represents the magnitude of the reflection coefficient via scattering parameters. A time domain analysis is provided by means of the eye diagram, which allows the study of the rise and fall time, jitter, and eye height and width of the two materials considered to be appropriate for the examination of composite substrates: one conventional substrate, FR4, and one more oriented to high-speed design constraints, N4000-13. Time domain analyses highlight the effect of increasing the rate for our purpose on the composite substrate for coupled or single-ended interconnections or routes on PCBs.