NRZ Code Research Articles

Various graded index plastic optical fiber performance signature capability with the optimum dispersion control for indoor coverage applications

Abstract This work has clarified the various graded index plastic optical fiber performance signature with the optimum dispersion control for indoor coverage applications. The plastic optical fibers that are deeply employed namely Polymethyl mathacrylate (PMMA), Epoxy, Polyfluorene and Cyclotene. Various plastic optical fiber dispersion is demonstrated against temperature variations. The different plastic fibers pulse broadening is clarified versus temperature variations. The previous plastic optical fibers types with respect to refractive index configuration and number of modes are clarified. Previous studies on PMMA/CYTOP plastic optical fibers attenuation is clarified against wavelength band variations. Various transmission techniques are applied to measure the fiber bandwidth and fiber channel bit rate. These transmission techniques are MTDM, NRZ and RZ coding. Different plastic fiber bandwidth against fiber channel distance is demonstrated based on NRZ, RZ and MTDM coding at room temperature. Different plastic fiber channel bit rate against fiber channel distance is studied and clarified based on NRZ, RZ and MTDM coding at room temperature. The choice of these plastic fibers are high temperature stability and more flexibility/reliability than other plastic fibers. The dispersion of these proposed plastic fibers can be controlled and managed with the control of temperature variations.

Research on the modulation format of 40Gb/s WDM-PON system

In order to meet the transmission needs of WDM-PON system, a WDM-PON full-duplex system based on reflective semiconductor optical amplifier (RSOA) remodulation was constructed in this paper. The downlink transmission rate of the system was 40Gb/s, and the downlink adopted three modulation formats, namely carrier suppression return to zero (CSRZ), optical duobinary (ODB) and quadrary pulse amplitude modulation (PAM4); the uplink transmission rate of the system was 10Gb/s, and the uplink adopted NRZ code. Through the simulation, the transmission performance of the system under these three modulation formats was compared and analysed?and the system uplink/downlink eye diagram and Q-value graph were obtained. The results show that the PAM4 signal has the strongest anti-dispersion capability and the ODB has the highest anti-nonlinear tolerance.

PENGEMBANGAN MODUL PRAKTIKUM UNTUK PERBANDINGAN UNJUK KERJA LINE CODING RZ DAN NRZ PADA JARINGAN FIBER OPTIK

The important thing to consider in the process of sending optical fiber network signals is theselection of line coding types. Line coding is a process of converting digital data into digital signals sothat they can be transmitted in optical fiber networks. Line codings commonly used are NRZ and RZ.Therefore, this research discussed the comparison of the performance of NRZ and RZ line codings infiber-optic networks in terms of Q-Factor, BER, and Eye Diagram. The result of this research was thecharacteristic form of the electric signal line coding NRZ with one data element using one signalelement, while in the RZ coding line, one data element used two signal elements. The maximum risetime variable using the RZ coding line is 0.3 bits, while the NRZ coding line is 0.7 bits. The bestrectangle shape model using line coding RZ is sine while line coding NRZ is exponential. Themaximum bit rate using the RZ coding line is 11.5 Gbps while using the NRZ coding line is 18 Gbps.The maximum transmission distance using the RZ and NRZ coding line is 75 km. Another output ofthis research is a practicum module that can be used by students of the Electrical Engineering StudyProgram to understand optical communication systems, especially line coding RZ and NRZ. Based onthe results of student assessments of 87.6% and the post-test score which is higher than the pre-testscore, the practicum module is feasible as teaching material.

Performance analysis of a 10 Gbps-60 GHz high speed RoF transmission system

Radio over fibre (RoF) is a revolutionary technology, which integrates radio and optical networks with a substantial bandwidth for wireless communication systems with minimum distortion and low cost. This paper investigates the performance of a radio over fibre system for high speed, moderate data of 10 Gbps encoded by RZ and NRZ code. The Mach-Zehnder modulator (MZM) is used to modulate the encoded data using 60 GHz radio frequency (RF). The results are obtained for the RoF system for the optical fibre of various lengths of 30, 45, 60 and 70 km. The performance of RZ and NRZ encoding is discussed using BER, Q factor, eye diagram and output power. It is observed that NRZ performs better than RZ for long haul communication.

Modulations and fading points

This document relates to NRZ and QPSK modulation codes or formats that have varying degrees of success in optical links. Indeed, these modulation formats undergo, during their path through the optical media, encounter the following limitations: (1) linear effects (attenuation, chromatic dispersion, polarization mode dispersion), (2) non-linear effects (Kerr, Raman and Brillouin effects). In addition to these limiting factors, the NRZ code in its propagation on the optical links encounters phenomena of fading of the signal as a function of the flow and the range. To reduce these fading phenomena, the QPSK code can be a solution. QPSK code makes it possible to reduce the number of fading points to the third on an optical link using a bit rate ranging from 10 to 30 Gbit s−1.

Simulation of Comparison from NRZ and RZ Pulse in Free Space Optics with Different Weather Conditions

FSO (Free Space Optic) is a form of optical technology communication by transmitting light to media free space. In the FSO system, the data transmission can be larger, namely 1-100 Gbps, and this is due to the large bandwidth width. FSO runs at a wavelength of 850 nm and 1550 nm. FSO is usually with a maximum distance of 2-4 km. This paper simulates the FSO optical transmission system using NRZ and RZ line coding in bright and rainy weather conditions. The parameters analyzed are Eye diagram, Optical Spec-trum, photocurrent, and received signal power. In the FSO line coding system, NRZ has an eye height value, received signal power and received photocurrent is greater than the RZ line coding at a distance of 1 km and 5 km in bright and rainy conditions. In the trial of this FSO communication system, it is better to use it at a distance of 1 km, because the received signal power is above 20 dBm and received photocurrent is still above 800 mA for NRZ and RZ line coding. This is due to the attenuation value of sunny weather conditions that are smaller between 0.2-3 dB/km, while in rain conditions between 4-17 dB/km.

A Study on the TT&C Engineering Telemetry Test

This paper uses the theoretical analysis of communication and signal system to calculate the power spectrum of NRZ code and PSK signal, which reveals the bandwidth selection problem often used in equipment, and derives the most commonly used calculation conversion formula in calibration. Finally, the analysis and compared two calibration methods.

Manchester encoder component for data processing IoT environment

Line encoding is crucial especially in data communication which part of internet of things environment. Line encoding doing encode raw bit stream and applying some rules before transmitting to transmission medium. Some example of encoding technique is: non-return zero encoding (NRZ), return-zero encoding, and Manchester encoding. Manchester coding technique have advantages compared to NRZ and RZ coding. Manchester coding can recognize bit interval and will have no problem to encode long same bit stream. Manchester encoder commonly built using logical XOR gate, with clock and bit stream as input and output of XOR gate will determined as encoded signal. The common design has a weakness since the clock is use in operation, and the output will be separate into two parallel bit stream. Common design also has spike glitch in some transitions. In this work, the new design of Manchester encoder using FPGA device is proposed to overcome common design problems and suitable to be implemented in IoT environment.

A Problem Analysis of RSOA-Based Optical Access

Using WDM multiplexing is one of the ways to increase PON bandwidth. But as WDM-PON is still expensive and difficult administered, the idea of using a Reflective Semiconductor Optical Amplifier (RSOA) is proposed. It can be installed in WDM-PON ONU network devices. A comprehensive problem analysis of various investigations is done relating to a performance of RSOA-based WDM-PON systems. The simulation model is created for RSOA-based WDM-PON access with downstream signal reusing in ONU for upstream transmission. This model helped in researching of RSOA abilities using different downstream and upstream signals modulation. Signal parameters were tested working with special software OptiSystem. Results were evaluated regarding such a characteristics as Q factor, signal attenuation, power and optical fiber length. It was found that RZ code was better suited in remodulation with RSOA; it achieved 1.25 Gbps signal transmission at a distance 8 times larger than that of the in NRZ code case. DOI: http://dx.doi.org/10.5755/j01.eie.22.2.14601

Analysis of intensity modulation performance in WDM-PON network

This paper mainly does research and analysis on anti-dispersive performance and anti-nonlinear performance for intensity modulation formats such as NRZ, RZ, CS-RZ, DRZ, MD-RZ in 40Gbps high-speed single-channel optical transmission system. It compares the five pattern modulation formats in dispersion tolerance, nonlinear tolerance, and advantages and disadvantages in transmission distance. Anti-nonlinear effect ability of CSRZ and RZ are stronger than that of NRZ code; in the single-channel transmission system, DRZ and improved modulation format MDRZ have better resistance for anti-nonlinear performance, so they are suitable for long-distance transmission. RZ has the minimum dispersion tolerance. NRZ has higher spectrum efficiency than RZ, and thus have a better dispersion tolerance. CSRZ code has higher spectral efficiency, higher dispersion tolerance and nonlinear tolerance than RZ code, making it more suitable for long distance transmission.

Research on the Modulation Performance in GPON System

This paper mainly does research and analysis on anti-dispersive performance and anti-nonlinear performance for intensity modulation formats such as NRZ, RZ, CS-RZ, DRZ, MD-RZ in 40Gbps high-speed single-channel optical transmission system. It compares the five pattern modulation formats in dispersion tolerance, nonlinear tolerance, and advantages and disadvantages in transmission distance. Anti-nonlinear effect ability of CSRZ, RZ are stronger than that of NRZ code; in the single-channel transmission system, DRZ and improved modulation format MDRZ have better resistance foranti-nonlinear performance, so they are suitable for long-distance transmission. RZ has the minimum dispersion tolerance. NRZ than RZ has higher spectrum efficiency than RZ, and thus have a better dispersion tolerance. CSRZ code has higher spectral efficiency, higher dispersion tolerance and nonlinear tolerance than RZ code, making it more suitable for long distance transmission.

The possibility of applying spectral redundancy in DWDM systems on existing long-distance FOCLs for increasing the data transmission rate and decreasing nonlinear effects and double Rayleigh scattering without changes in the communication channel

A new method of data transmission in DWDM systems along existing long-distance fiber-optic communication lines is proposed. The existing method, e.g., uses 32 wavelengths in the NRZ code with an average power of 16 conventional units (16 units and 16 zeros on the average) and transmission of 32 bits/cycle. In the new method, one of 124 wavelengths with a duration of one cycle each (at any time instant, no more than 16 obligatory different wavelengths) and capacity of 4 bits with an average power of 15 conventional units and rate of 64 bits/cycle is transmitted at every instant of a 1/16 cycle. The cross modulation and double Rayleigh scattering are significantly decreased owing to uniform distribution of power over time at different wavelengths. The time redundancy (forward error correction (FEC)) is about 7% and allows one to achieve a coding enhancement of about 6 dB by detecting and removing deletions and errors simultaneously.

Polarization Jitters Caused by Fiber Nonlinearity in PM Optical Communication System

The phenomenon of polarization jitters caused by fiber nonlinearity is investigated. A general formula about the polarization jitter is concluded in polarization multiplexing (PM) system based on two orthogonal linear polarization states when the best polarization correction is used. A 100 Gb/s PM system based on NRZ code is investigated by simulation, and the Stocks parameter about polarization jitter and Poincare sphere diagrams are got for different power and phase difference of two orthogonal polarized light. The results show that the polarization jitters will be suppressed when the combined PM signal is the linear or circular polarization state.

Investigation of Allowed Channel Spacing for Differently Modulated Optical Signals in Combined HDWDM Systems

By the reduction of channel spacing in WDM system, it's possible to add some extra channels to it and in that way to increase the total transmission capacity of the used fibre and postpone bottleneck effect of core networks. But using the alternative modulation formats, such as differential phase shift keying with non - return - to zero coding (NRZ - DPSK) or two - states polarization shift keying (2 - POLSK), instead of traditional on - off keying with NRZ coding (NRZ - OOK), it's possible to achieve the lower bit error ration BER level and channel's tolerance to transmission impairments, such as inter-channel nonlinearities and crosstalk. The study object of this work is the allowed channel spacing in combined HDWDM systems, if modulation format in each system's channel are different. For numerical evaluation of modulation formats simultaneous propagation in WDM system, which consists of three channels with 10 Gbit/s bit rate each, simulation model in OptSim software were introduced. The obtained BER values of each channel were compared with the results of traditional systems, which are using only one of mentioned above optical signal modulation formats. These results will allow choosing development strategy in construction of new optical network and improving already existing network infrastructure. 1ll. 9, bibl. 8, tabl. 1 (in English; abstracts in English and Lithuanian).http://dx.doi.org/10.5755/j01.eee.112.6.437

Effect of seasonal temperature fluctuations on performance of 160 Gbps transmission with adjustable chromatic dispersion compensation

In this paper, effect of seasonal temperature fluctuations on performance of chromatic dispersion compensated 160 Gbps optical fiber networks is investigated. Compensation of temperature dispersion effects on single mode fiber (SMF) is obtained by adjusting the length of the dispersion compensation fiber (DCF) as compensation and compensation slope factors of SMF fiber vary with temperature. Based on temperature dependence models and measurements, simulation studies have been carried out and the obtained results show expected quantitative compensation requirements for seasonal thermal effects. The range of temperatures considered corresponds to seasonal ones for Muscat area with changes from −10°C to 60°C. This has been done for typical optical fiber spans of SMF and DCF fibers for 160 Gbps rates. In addition to this, the results that the NRZ coding format is more tolerant to temperature changes than the RZ format.

PMD induced performance deterioration in NOLM switch

Performance deterioration induced by the first- and second-order PMD in the basic NOLM switch unit in the digital optical communication system and analog microwave photonic communication system is studied by using the split-step Fourier method that can solve the coupled nonlinear Schrödinger equation, the three-dimensional Poincare sphere theory and the Jones matrix method. The simulation results show that the switch performance is badly deteriorated by PMD and the impact of the second-order PMD is far more than that of the first-order PMD when NOLM is at a high working speed or a large modulation bandwidth. In the digital optical communication system, the optical eye graphs of pulses and the extinction ratio of NOLM are deteriorated by PMD and it can partially reduce the impact of PMD to use the right code pattern, in which the performance of CRZ code with positive chirp is better than that of RZ code and the performance of RZ code is better than that of NRZ code when they have the same average power. In the analog microwave photonic communication system, PMD induces the descent of the SNR and the side lobe leak of the signal.

Design of an all-optical NOT XOR gate based on cross-polarization modulation in a semiconductor optical amplifier

In this work, we have discussed the physical phenomena involved in the manifestation of the cross-polarization modulation (XPolM) effect in a semiconductor optical amplifier (SOA), namely the eigenaxes modification, the structural birefringence perturbation and the polarization gain dispersion. We demonstrate that the XPolM effect can rotate the polarization-state of a CW beam by 73.5° when the power of a control beam changes from 0 to 300 μW. The control and CW beams are introduced into the amplifier with a linear polarization near to the unperturbed amplifier TM axis where the waveguide eigenaxes modification presented the strongest participation in the XPolM effect in the used SOA. Finally, we experimentally show Boolean NOT XOR operation with input logic signals modulated with a 2.5 Gb/s NRZ code with a pseudo-random data sequence of 2 23−1 length. The NOT XOR gate utilizes a single SOA as non-linear element and it needs neither an inversion stage nor an additional synchronized clock.

Impact of optical (de)multiplexers on 40 Gbit/s WDM transmission system

The impact of (de)multiplexers on 40 Gbit/s WDM system is investigated for NRZ and RZ coding formats. Performances of (de)multiplexers with different crosstalk, filter bandwidth and channel spacing are systematically analyzed to get the best system performance for 40 Gbit/s WDM transmission system with high spectral efficiency. The limitations imposed by misalignment and cascade of filters are also discussed.

Optical satellite communications with Erbium doped fiber amplifiers

For implementing an optical free-space transmission system at data rates up to 10 Gbit/s, commercially available devices developed for terrestrial fiber optic applications may be employed to advantage. We designed, set up and tested a breadboard consisting of an NRZ/RZ transmitter with a booster amplifier of 1 W optical output power and an optically preamplified direct detection receiver. The main objective was to determine the receiver sensitivity and assess critical components. With the breadboard parameters optimized, the required average number of photons per bit at the receiver input was 55 for a bit error probability of BEP=10 −6 in case of NRZ coding. We further demonstrated a sensitivity improvement of about 1 dB by applying RZ coding. The measurements yielded excellent agreement with simulations performed with a tool especially designed for this purpose.

Performance Optimization of Optically Preamplified Receivers for Return-to-zero and Non Return-to-zero Coding

We determine optimum bandwidths for optical and electrical filters in optically preamplified receivers, both for NRZ coding and RZ coding. Our simulations clearly reveal the trade-offs to be made when optimizing bandwidths: NRZ is typically limited by intersymbol interference, while RZ is limited by energy truncation. Thus, RZ allows for tighter filtering, leading to near quantum limited performance. Further, RZ systems are less susceptible to suboptimum filtering. We also show that the use of RZ with duty cycles below 33% only leads to minor additional receiver sensitivity improvements at the expense of impractically higher receiver bandwidths. Employing an RZ duty cycle of 33%, we achieved a receiver sensitivity of 52 ppb at a data rate of 10 Gbit/s, which is only 1.4 dB off the quantum limit.