scholarly journals Phase Noise Cancellation in Coherent Communication Systems Using a Radio Frequency Pilot Tone

2019 ◽  
Vol 9 (21) ◽  
pp. 4717 ◽  
Author(s):  
Tianhua Xu ◽  
Cenqin Jin ◽  
Shuqing Zhang ◽  
Gunnar Jacobsen ◽  
Sergei Popov ◽  
...  
Keyword(s):  
Radio Frequency ◽  
Phase Noise ◽  
Communication Systems ◽  
Optical Transmission ◽  
Dispersion Compensation ◽  
Optical Fiber Communication ◽  
Noise Cancellation ◽  
Least Mean Square ◽  
Modulation Formats ◽  
The Impact

Long-haul optical fiber communication employing digital signal processing (DSP)-based dispersion compensation can be distorted by the phenomenon of equalization-enhanced phase noise (EEPN), due to the reciprocities between the dispersion compensation unit and the local oscillator (LO) laser phase noise (LPN). The impact of EEPN scales increases with the increase of the fiber dispersion, laser linewidths, symbol rates, signal bandwidths, and the order of modulation formats. In this work, the phase noise cancellation (PNC) employing a radio frequency (RF) pilot tone in coherent optical transmission systems has been investigated. A 28-Gsym/s QPSK optical transmission system with a significant EEPN has been implemented, where the carrier phase recovery (CPR) was realized using the one-tap normalized least-mean-square (NLMS) estimation and the differential phase detection (DPD), respectively. It is shown that the RF pilot tone can entirely eliminate the LPN and efficiently suppress the EEPN when it is applied prior to the CPR.

scholarly journals Impact of Equalization-Enhanced Phase Noise on Digital Nonlinearity Compensation in High-Capacity Optical Communication Systems

Sensors ◽  
2020 ◽  
Vol 20 (15) ◽  
pp. 4149 ◽  
Author(s):  
Jiazheng Ding ◽  
Tianhua Xu ◽  
Cenqin Jin ◽  
Ziyihui Wang ◽  
Jian Zhao ◽  
...  
Keyword(s):  
Phase Noise ◽  
Optical Communication ◽  
Communication Systems ◽  
Laser Linewidth ◽  
Dual Polarization ◽  
Transmission Systems ◽  
Modulation Formats ◽  
Information Rates ◽  
Optical Communication Systems ◽  
The Impact

Equalization-enhanced phase noise (EEPN) can severely degrade the performance of long-haul optical fiber transmission systems. In this paper, the impact of EEPN in Nyquist-spaced dual-polarization quadrature phase shift keying (DP-QPSK), dual-polarization 16-ary quadrature amplitude modulation (DP-16QAM), and DP-64QAM optical transmission systems is investigated considering the use of electrical dispersion compensation (EDC) and multi-channel digital backpropagation (MC-DBP). Our results demonstrate that full-field DBP (FF-DBP) is more susceptible to EEPN compared to single-channel and partial-bandwidth DBP. EEPN-induced distortions become more significant with the increase of the local oscillator (LO) laser linewidth, and this results in degradations in bit-error-rates (BERs), achievable information rates (AIRs), and AIR-distance products in optical communication systems. Transmission systems using higher-order modulation formats can enhance information rates and spectral efficiencies, but will be more seriously degraded by EEPN. It is found that degradations on AIRs, for the investigated FF-DBP schemes, in the DP-QPSK, the DP-16QAM, and the DP-64QAM systems are 0.07 Tbit/s, 0.11 Tbit/s, and 0.57 Tbit/s, respectively, due to the EEPN with an LO laser linewidth of 1 MHz. It is also seen that the selection of a higher-quality LO laser can significantly reduce the bandwidth requirement and the computational complexity in the MC-DBP.

scholarly journals Performance Analysis of Subcarrier Multiplexed Optical Transmission System for QPSK Data

2020 ◽  
Vol 9 (2) ◽  
pp. 466-476
Keyword(s):  
Optical Transmission ◽  
Dispersion Compensation ◽  
Chromatic Dispersion ◽  
Transmission System ◽  
Laser Source ◽  
Radio Link ◽  
Link Distance ◽  
Performance Results ◽  
The Impact ◽  
Dispersion And Attenuation

This paper focuses on the impact of different parameters on the performance of the Subcarrier Multiplexed Optical Transmission System for the application on radio link via optical fiber. Performance results are evaluated for QPSK data format for ODSB and OSSB modulation of Microwave subcarriers with digital NRZ coded random data patterns. The four subsystems of QPSK modulators are at 400, 500, 600, 700 MHz subcarrier frequencies with frequency spacing of 100 MHz. The power of subcarriers is decreasing with increasing the link distance due to dispersion and attenuation. By using dispersion compensation fiber, the link distance has been enhanced from 100 km to 240 km successfully. The impact of chromatic dispersion has been reduced in OSSB by using dual-electrode MZM. The constellation diagram also confirms that the phase of the signal after traveling through the link is changing due to dispersion. The phase is the same for subcarrier 600 MHz & 700 MHz for ODSB and OSSB in QPSK SCM. The impact of linewidth and responsivity on SNR has also analyzed to evaluate the performance. It is concluded that the maximum SNR is decreasing with increase in the linewidth of laser source and increasing with the increase in responsivity of PIN diode for the same fiber length in SCM transmission.

Research on Application of Tunable Dispersion Compensation Technology in Optical Fiber Communication Systems

2013 ◽  
Vol 401-403 ◽  
pp. 1956-1959
Author(s):  
Wen Xuan Gai
Keyword(s):  
Communication Systems ◽  
Dispersion Compensation ◽  
Optical Fiber Communication ◽  
Fiber Grating ◽  
Basic Principles ◽  
Fiber Communication ◽  
Future Direction ◽  
Chirped Fiber Grating ◽  
Research On Application ◽  
Communications System

For high bit-rate optical communications system, the changes in temperature or power fluctuations are due to the dispersion of the dispersion tolerance than the system. Therefore, the dispersion compensation unit must have the functionality to adapt to the dynamic generation of tunable optical communication network development. This article describes several dynamic tunable compensation techniques and the basic principles of the performance characteristics of the situation at home and abroad, including the chirped fiber grating method, the virtual image phased array method, GT interferometer method, the array method and the planar waveguide grating method, and a brief discussion of tunable dispersion compensation technology in the future direction of development.

scholarly journals Mitigating the Impact of Noise on Nonlinear Frequency Division Multiplexing

2020 ◽  
Vol 10 (24) ◽  
pp. 9099
Author(s):  
Stella Civelli ◽  
Enrico Forestieri ◽  
Marco Secondini
Keyword(s):  
Dispersion Compensation ◽  
Kerr Nonlinearity ◽  
Optical Fiber Communication ◽  
Frequency Division Multiplexing ◽  
Nonlinear Frequency ◽  
Frequency Division ◽  
Fiber Communication ◽  
Range Rate ◽  
Conventional Systems ◽  
The Impact

In the past years, nonlinear frequency division multiplexing (NFDM) has been investigated as a potentially revolutionary technique for nonlinear optical fiber communication. However, while NFDM is able to exploit the Kerr nonlinearity, its performance lags behind that of conventional systems. In this work, we first highlight that current implementations of NFDM are strongly suboptimal, and, consequently, oversensitive to noise: the modulation does not ensure a large minimum distance between waveforms, while the detection is not tailored to the statistics of noise. Next, we discuss improved detections strategies and modulation techniques, proposing some effective approaches able to improve NFDM. Different flavors of NFDM are compared through simulations, showing that (i) the NFDM performance can be significantly improved by employing more effective detection strategies, with a 5.6 dB gain in Q-factor obtained with the best strategy compared to the standard strategy; (ii) an additional gain of 2.7 dB is obtained by means of a simple power-tilt modulation strategy, bringing the total gain with respect to standard NFDM to 8.3 dB; and (iii) under some parameters range (rate efficiency η≤30%), the combination of improved modulation and detection allows NFDM to outperform conventional systems using electronic dispersion compensation.

scholarly journals Performance Enhancement of DWDM-FSO Optical Fiber Communication Systems Based on Hybrid Modulation Techniques under Atmospheric Turbulence Channel

Photonics ◽  
2021 ◽  
Vol 8 (11) ◽  
pp. 464
Author(s):  
Mohammed R. Hayal ◽  
Bedir B. Yousif ◽  
Mohamed A. Azim
Keyword(s):  
Optical Fiber ◽  
Atmospheric Turbulence ◽  
Adaptive Optics ◽  
Communication Systems ◽  
Optical Fiber Communication ◽  
Passive Optical Network ◽  
Communication Link ◽  
Fiber Communication ◽  
Digital Pulse ◽  
The Impact

In this paper, we enhance the performance efficiency of the free-space optical (FSO) communication link using the hybrid on-off keying (OOK) modulation, M-ary digital pulse position modulation (M-ary DPPM), and M-pulse amplitude and position modulation (M-PAPM). This work analyzes and enhances the bit error rate (BER) performance of the moment generating function, modified Chernoff bound, and Gaussian approximation techniques. In the existence of both an amplified spontaneous emission (ASE) noise, atmospheric turbulence (AT) channels, and interchannel crosstalk (ICC), we propose a system model of the passive optical network (PON) wavelength division multiplexing (WDM) technique for a dense WDM (DWDM) based on the hybrid fiber FSO (HFFSO) link. We use eight wavelength channels that have been transmitted at a data rate of 2.5 Gbps over a turbulent HFFSO-DWDM system and PON-FSO optical fiber start from 1550 nm channel spacing in the C-band of 100 GHz. The results demonstrate (2.5 Gbps × 8 channels) 20 Gbit/s-4000 m transmission with favorable performance. In this design, M-ary DPPM-M-PAPM modulation is used to provide extra information bits to increase performance. We also propose to incorporate adaptive optics to mitigate the AT effect and improve the modulation efficiency. We investigate the impact of the turbulence effect on the proposed system performance based on OOK-M ary- PAPM-DPPM modulation as a function of M-ary DPPM-PAPM and other atmospheric parameters. The proposed M-ary hybrid DPPM-M-PAPM solution increases the receiver sensitivity compared to OOK, improves the reliability and achieves a lower power penalty of 0.2–3.0 dB at low coding level (M) 2 in the WDM-FSO systems for the weak turbulence. The OOK/M-ary hybrid DPPM-M-PAPM provides an optical signal-to-noise ratio of about 4–8 dB of the DWDM-HFFSO link for the strong turbulence at a target BER of 10−12. The numerical results indicate that the proposed design can be enhanced with the hybrid OOK/M-DPPM and M-PAPM for DWDM-HFFSO systems. The calculation results show that PAPM-DPPM has increased about 10–11 dB at BER of 10−12 more than the OOK-NRZ approach. The simulation results show that the proposed hybrid optical modulation technique can be used in the DWDM-FSO hybrid links for optical-wireless and fiber-optic communication systems, significantly increasing their efficiency. Finally, the use of the hybrid OOK/M-ary DPPM-M-PAPM modulation schemes is a new technique to reduce the AT, ICC, ASE noise for the DWDM-FSO optical fiber communication systems.

A 802.15.3c/802.11ad dual mode phase noise cancellation for 60 GHz communication systems

2015 ◽  
Author(s):  
Liang-Yu Huang ◽  
Chia-Yi Wu ◽  
Chun-Yi Liu ◽  
Wei-Chang Liu ◽  
Chih-Feng Wu ◽  
...  
Keyword(s):  
Phase Noise ◽  
Communication Systems ◽  
Noise Cancellation ◽  
60 Ghz ◽  
Dual Mode

scholarly journals High-speed visible light communication systems based on Si-substrate LEDs with multiple superlattice interlayers

PhotoniX ◽  
2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Fangchen Hu ◽  
Shouqing Chen ◽  
Yuyi Zhang ◽  
Guoqiang Li ◽  
Peng Zou ◽  
...  
Keyword(s):  
Visible Light ◽  
Radio Frequency ◽  
Communication Systems ◽  
High Speed ◽  
Visible Light Communication ◽  
Data Rate ◽  
Si Substrate ◽  
Theoretical Derivation ◽  
Wall Plug Efficiency ◽  
The Impact

AbstractHigh-speed visible light communication (VLC), as a cutting-edge supplementary solution in 6G to traditional radio-frequency communication, is expected to address the tension between continuously increased demand of capacity and currently limited supply of radio-frequency spectrum resource. The main driver behind the high-speed VLC is the presence of light emitting diode (LED) which not only offers energy-efficient lighting, but also provides a cost-efficient alternative to the VLC transmitter with superior modulation potential. Particularly, the InGaN/GaN LED grown on Si substrate is a promising VLC transmitter to simultaneously realize effective communication and illumination by virtue of beyond 10-Gbps communication capacity and Watt-level output optical power. In previous parameter optimization of Si-substrate LED, the superlattice interlayer (SL), especially its period number, is reported to be the key factor to improve the lighting performance by enhancing the wall-plug efficiency, but few efforts were made to investigate the influence of SLs on VLC performance. Therefore, to optimize the VLC performance of Si-substrate LEDs, we for the first time investigated the impact of the SL period number on VLC system through experiments and theoretical derivation. The results show that more SL period number is related to higher signal-to-noise ratio (SNR) via improving the wall-plug efficiency. In addition, by using Levin-Campello bit and power loading technology, we achieved a record-breaking data rate of 3.37 Gbps over 1.2-m free-space VLC link under given optimal SL period number, which, to the best of our knowledge, is the highest data rate for a Si-substrate LED-based VLC system.

Performance Analysis of Laser Phase Noise Compensated COOFDM System

2020 ◽  
Vol 41 (4) ◽  
pp. 445-451
Author(s):  
Divya Dhawan ◽  
Neena Gupta
Keyword(s):  
Phase Noise ◽  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
High Speed ◽  
Extinction Ratio ◽  
Symbol Error Rate ◽  
Coherent Detection ◽  
Error Vector Magnitude ◽  
Modulation Formats ◽  
Promising Solution

AbstractOrthogonal Frequency Division Multiplexing along with the coherent detection and spectrally efficient modulation formats is a promising solution for long haul and high speed communication systems. Although they offer significant advantages which make them suitable for high speed and long haul communication systems they all are susceptible to phase noise. In this paper a combination of RF-pilot-based approach followed by pilot-based equalization approach is used for laser phase noise compensation. The various parameters such as drive voltage, bias voltage and extinction ratio are optimized to get the optimum performance from the proposed scheme. The designed system is then analyzed in terms of Symbol Error Rate (SER), constellation diagrams and error vector magnitude using various types of Quadrature Amplitude Modulation (QAM) formats.

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