Manchester Modulation Research Articles

Combining modified Manchester modulation with optical equalization for improved dispersion tolerance in IM/DD access networks

In this paper the intensity modulation and direct detection of an optical link utilizing a Modified Manchester (MM) signal at the bitrate of 10 Gb/s and 25 Gb/s are presented for long-reach optical access networks. First-order and second-order optical equalizer were utilized to compensate the distortion in MM signal waveform caused by the chromatic dispersion in standard single mode fiber (SSMF). The assessment of the system performance was centered on bit error rate (BER), power penalty, eye diagrams and chromatic dispersion tolerance. Based on the calculated results the use of second-order optical equalizer, can extend the transmission distance by 20 km (SSMF) and 3.5 km at 10 Gb/s and 25 Gb/s, respectively. Based on the calculated results, the use of second-order optical equalizer is therefore promising in the next generation of long-reach optical access networks.

Performance evaluation of four‐level modified Manchester modulation format for high‐speed optical transmission systems

A new multilevel modulation scheme centred on Manchester signalling known as four-level modified Manchester (4-MM) modulation format is envisioned and proven statistically for high-speed optical fibre transmission links. Similarly, the bit error rate (BER) assessment version has been developed for the envisioned 4-MM format. The performance of new 4-MM is examined and compared with conventional Manchester modulation, binary MM modulation, and four-level pulse amplitude modulation (4-PAM) formats in relation to receiver sensitivity, spectral efficiency, and chromatic dispersion tolerance. Therefore, the computed receiver sensitivity and chromatic dispersion tolerance at 10−9 BER of the envisioned 4-MM are −21.5 dBm and 95 ps/nm, respectively. The receiver sensitivity of 4-MM was improved by 3 dB in comparison with 4-PAM in a back-to-back configuration. Similarly, assessment of results indicates that 4-MM technique has a distinct benefit in comparison with binary MM and 4-PAM in achieving a dynamic role in the subsequent generation of high-speed optical access and short reach networks where power efficiency is of critical important.

Transmission of 160-Gb/s Modified Manchester modulation over WDM system

ABSTRACTThe paper examines the performance of Modified Manchester (MM) modulation scheme over wavelength division multiplexing (WDM) in high-speed optical communication links. The MM as a new modulation technique has a narrow spectral width compared to conventional Manchester coding, which allows its implementation in WDM systems beneficial. In this study, the performance characteristics of MM and conventional Manchester modulation formats are assessed in WDM system at 10 Gb/s bitrate for each channel, for the least allowable channel spacing as well as tolerance to chromatic dispersion (CD). It is revealed from the results of simulation that MM performs meaningfully well in comparison with conventional Manchester in terms of tolerance against narrow optical filtering, spectral efficiency, which is improved by 32% and CD tolerance, which is improved by +100 ps/nm. Sixteen wavelength channels (16 × 10 Gb/s) are modulated to provide 160 Gb/s data capacity, which was transmitted successfully over 224 km standard single mode fibre (SSMF) using MM while the conventional Manchester only covered about 157 km.

Novel Manchester-Based Multilevel Signaling for High-Speed Optical Communication Systems

Abstract In this paper, the performance of a novel multilevel signaling based on Manchester code namely four-level Manchester Coding (4-MC) technique is investigated for next generation high-speed optical fiber communication links. The performance of 4-MC is studied and compared with conventional Manchester modulation and four-level pulse amplitude modulation (4-PAM) formats in terms of receiver sensitivity, spectral efficiency and dispersion tolerance at the bit rate of 40 Gb/s. The bit error rate (BER) calculation model for the proposed multilevel scheme has also been developed. The calculated receiver sensitivity and the chromatic dispersion tolerance at the BER of 10–9 of the proposed scheme are −22 dBm and 67.5 ps/nm, respectively. It is observed that, 4-MC scheme is superior in comparison to 4-PAM by 3.5 dB in terms of receiver sensitivity in back-to-back scenario. Therefore, the proposed scheme can be considered as an alternative to current 4-PAM system.

Performance analysis of mode division multiplexing IS-OWC system using Manchester, DPSK and DQPSK modulation techniques

In this work, a high capacity mode division multiplexing (MDM) based Inter-Satellite Optical Wireless system is presented. In order to increase capacity of the system, 64 linearly polarized modes are incorporated in the system. The proposed MDM Inter-Satellite Optical Wireless Communication system has been designed using various modulation techniques such as Manchester, DPSK and DQPSK at the different distances of 750–3750 km and data rates of 10, 20 and 40 Gbps. Results have been compared on the basis of Eye Diagrams, Q-factor as well as minimum Bit Error rate. The comparative analysis shows at the bit rate of 10 Gbps, DQPSK modulation technique provides highest Quality factor of 32.01 followed by DPSK and Manchester Modulation. DQPSK Modulation technique shows best performance till 40 Gbps and Manchester shows least. It is also observed that on increasing bit rates from 10 Gbps to 40 Gbps, Quality factor degrades. Proposed MDM IS-OWC system is reliable to use, flexible, cost effective and useful for long distance communication.

Modified Manchester modulation format for high‐speed optical transmission systems

A novel advanced modulation format based on Manchester signalling is proposed and assessed for high-speed optical communication systems. The new advanced modulation format known as modified Manchester derived from the combination of Manchester and vestigial sideband (VSB) techniques. Its performance assessed and compared in terms of spectral efficiency, chromatic dispersion tolerance and receiver sensitivity against conventional Manchester, return-to-zero (RZ) and non-RZ (NRZ) (with the same spectral width). The optimisation of the optical filter that performed the VSB filtering on the Manchester signal and its detuning frequency results in the compression of the spectral width of the Manchester signal and thereby enhanced the spectral efficiency of the modified Manchester to about 31.3%. This results in the improvement of dispersion tolerance to ∼140 ps/nm. In comparison with conventional modulation formats, the proposed system can improve the dispersion tolerance by three times more than conventional Manchester, which is 44 ps/nm, and twice more than NRZ, which is 51.8 ps/nm and has a better dispersion tolerance of 31 ps/nm than RZ with dispersion tolerance of 109 ps/nm at a bit-error-rate of 10−9. The improvement in the proposed modulation performance achieved without utilisation of any dispersion compensation module or electronic equalisation.

Mitigation of mode partition noise in quantum-dash Fabry-Perot mode-locked lasers using Manchester encoding and balanced detection.

We propose the use of Manchester encoding in conjunction with balanced detection to overcome the mode partition noise (MPN) limit of quantum-dash Fabry-Perot mode-locked lasers (QD-MLLs) used as multi-wavelength sources in short-reach applications. The proposed approach is demonstrated for a 10-mode laser, each carrying a 10-Gb/s signal. We show that bit-error-rate floors as high as 10-4 when traditional non-return-to-zero (NRZ) modulation is employed with a single-ended detection scheme can be pushed below 10-9 thanks to the introduction of Manchester encoding together with balanced detection. The benefit of the scheme could be attributed to the spectral shift of the Manchester spectrum, resulting in a smaller overlap with the high-relative intensity noise (RIN) region present at low frequencies, and the use of balanced detection. We clarify the origin of the performance improvement through comparisons of single-ended and balanced detection and the use of a RIN emulation technique. We unambiguously show that the use of balanced detection plays the leading role in MPN mitigation enabled by Manchester modulation.

BER Performance of NRZ-OOK and Manchester Modulation in Indoor Wireless Infrared Links

This paper describes a novel approach to theevaluation of the bit error rate (BER) performance ofoptical wireless links that takes into account shotnoise, fluorescent light interference, and intersymbol interference (ISI) from both multipathdispersion and high-pass filtering (HPF) at thereceiver. The calculation of the BER is achieved withthe use of an efficient numerical technique based onnonclassical Gauss Quadrature Rules. Fluorescent lightinterference is modeled as a Fourier series expansionwith coefficients taken from measurements, whilemultipath-induced ISI is calculated by using previouslyreported IR channel models. Application of the techniquepresented here allows for the calculation of the optimumHPF cutoff frequency that minimizes the overallperformance penalty. Finally, as an application of this method, the BER performance of NRZ-OOK andManchester (2-PPM) modulation is evaluated and numericalresults are presented for different linkscenarios.

Fiberoptic Data Bus Interface Hardware Realisation

Bus interface cirsuit for a fiberoptic data bus differs from a copper wire data bus. While unipolar manchester modulation is used with a fiberoptic data bus, a biphase manchester modulation is used in the copper wire data bus.This paper suggests a design of a bus interface circuit for any fiberoptic data bus for fly-by-light, stores management, data transmission, etc., compatible with the MIL-STD-1553B. This is applicable for use on board aircraft, ships. tanks, etc.