Differential Phase Shift Keying Data Research Articles

Performance analysis of hybrid WDM-OTDM optical multicast overlay system employing 120 Gbps polarization and subcarrier multiplexed unicast signal with 40 Gbps multicast signal

In this paper, we have propose and investigated the performance of hybrid WDM-OTDM optical multicast overlay system which employs 120Gbps unicast and 40Gbps multicast data operating over SMF+DCF and amplifier link in C-band. The polarization and subcarrier multiplexed modulation formats are used to obtain 120Gbps unicast data and DPSK (differential phase shift keying) modulation format for 40Gbps multicast data transmission. In multicast operation, DPSK data is superimposed on to multiplexed unicast data channels. The impact of extinction ratio, input power and transmission distance on the performance of proposed system in terms of output optical power, BER and Q-factor has been investigated for both unicast and multicast data. We have also concluded that polarization and subcarrier multiplexed modulation formats are promising option to increase per channel capacity and less vulnerable to CD and PMD. In addition, the proposed system using hybrid modulation techniques offers higher bandwidth utilization efficiency at higher per channel data rate than conventional modulation formats.

Wavelength division multiplexing passive optical networks (WDM PONs) With Downstream DPSK and Upstream Remodulated OOK using Injection-Locked Fabry-Perot Laser Diodes (FP-LDs)

Wavelength Division Multiplexing-Passive Optical Network (WDM-PON) system based on the injection locked Fabry-Perot laser diode (FP-LD) has been investigated. The system has been demonstrated without dispersion compensation for both 10Gbps Differential phase-shift keying (DPSK) downstream signal and 2.5Gbps On-off keying (OOK) upstream signal respectively. Error free transmission over 50-km is achieved by tailoring the parameters of the FP-LD. The BER performance of our system shows that the injection locked FP-LD is a low cost effective colourless transmitter for high-speed WDM-PONs. Full Text: PDF References E. Wong, "Next-Generation Broadband Access Networks and Technologies", J. Lightwave Technol. 30(4), 597 (2012). CrossRef F.T. An, D. Gutierrez, K.S. Kim, J.W. Lee, L.G. Kazovsky, "SUCCESS-HPON: A next-generation optical access architecture for smooth migration from TDM-PON to WDM-PON", IEEE Commun. Mag. 43(11), S40 (2005). CrossRef S.-J. Park, C.-H. Lee, K.-T. Jeong, H.-J. Park, J.-G. Ahn, K.-H. Song, "Fiber-to-the-home services based on wavelength-division-multiplexing passive optical network", J. Lightwave Technol. 22, 2582 (2004). CrossRef C.W. Chow, C.H. Yeh, "Using Downstream DPSK and Upstream Wavelength-Shifted ASK for Rayleigh Backscattering Mitigation in TDM-PON to WDM-PON Migration Scheme", IEEE Photon. J. 5(2), 7900407 (2013). CrossRef J. He, D. Yang, L. Chen, "A full-duplex radio-over-fiber system with differential phase-shift keying signals", J. Phys. Conf. 276, 012062 (2011). CrossRef L.Y. Chan, C.K. Chan, D.T.K Tong, E Tong, L.K. Chen, "Upstream traffic transmitter using injection-locked Fabry-Perot laser diode as modulator for WDM access networks", Electron. Lett. 38(I), 43 (2002). CrossRef Z. Xu, Y. J. Wen, C. J. Chae, Y. Wang, C. Lu, Proc. Opt. Fiber Commun. Conf. (OFC06), JThB72 (2006). C.H. Yeh, C.W. Chow, H.Y. Chen, J.Y. Sung, Y.L. Liu, "Demonstration of using injection-locked Fabry-Pe?rot laser diode for 10?Gbit/s 16-QAM OFDM WDM-PON", Electron. Lett. 48(15), 940 (2012). CrossRef J. H. Lee et al., "Single, Depolarized, CW Supercontinuum-Based Wavelength-Division-Multiplexed Passive Optical Network Architecture With C-Band OLT, L-Band ONU, and U-Band Monitoring", IEEE J. Light. Tech. 25(10), 2891 (2007). CrossRef Q.T. Nguyen et al., "Bidirectional Transmission in Colourless WDM-PON based on Injection-Locked Fabry-Perot Laser at 2.5 Gbit/s using Low-Cost Seeding Source", in: Proc. Eur. Conf. Opt. Commun. (ECOC), Vienna, Austria, Paper 6.5.1, (2009). DirectLink T. Yoshida, S. Kimura, H. Kimura, K. Kumozaki, T. Imai, "A new single-fiber 10-gb/s optical loopback method using phase Modulation for WDM optical access networks", J. Lightw. Technol. 24,786 (2006) CrossRef W. Hung, C.-K. Chan, L.-K. Chen, F. Tong, "An optical network unit for WDM access networks with downstream DPSK and upstream remodulated OOK data using injection-locked FP laser", IEEE Phot. Techn. Lett. 15(10), 1476 (2003). CrossRef OptiSystem Package from Optiwave.

A bidirectional radio-over-fiber system using differential phase-shift keying signals for downstream and remodulated OOK for upstream

Radio-over-fiber (ROF) is a promising technology to achieve future broadband access requirements with reliability, transparency and flexibility. We propose a novel full-duplex bi-directional radio-over-fiber (ROF) system transmitting 10Gb/s differential phase-shift keying (DPSK) signals at the central office (CO) for downstream and ON–OFF keying (OOK) re-modulation of the downlink carrier at the base station (BS) for upstream. As the same optical carrier is used for both uplink and downlink, no additional light source is required at the BS, which significantly reduces the cost, improves the wavelength utilization efficiency and simplifies the overall system. The simulation results show that the downstream 10Gb/s DPSK data and the upstream 1Gb/s OOK data can transmit over 50km single-mode fiber successfully without dispersion compensation. The results show that this scheme provides a practical solution to meet the data rate and cost requirement of tomorrow's ROF access networks.

All-optical simultaneous drop and wavelength conversion of DPSK data

We demonstrate an all-optical scheme for the simultaneous drop and wavelength conversion of bursts of data from a continuous stream of differential phase-shift keyed (DPSK) signals. This function is obtained in a single semiconductor optical amplifier Mach-Zehnder interferometer thanks to proper nonlinear interaction of the data stream and an optical gate signal at different wavelength. Fast switching-time enabling wavelength shifting operation on continuous DPSK data stream at 10 and 40 Gb/s without any bit loss is reported. Corresponding measured power penalties are negligible at 10 Gb/s and about 1.7 dB at 40 Gb/s.

Rapid Reconfigurable OCDMA System Using Single-Phase Modulator for Time-Domain Spectral Phase Encoding/Decoding and DPSK Data Modulation

An optical-code-division-multiple-access (OCDMA) system with a novel modulation scheme for simultaneous generation of time-domain spectral phase encoding/decoding (SPE/SPD) and differential phase-shift keying (DPSK) data modulation that can be potentially rapidly reconfigured using only a single-phase modulator (PM) is proposed and experimentally demonstrated. The time-domain SPE is realized by stretching and compressing the ultrashort optical pulse through two-chirped fiber Bragg gratings with opposite dispersion and a high-speed PM for optical code (OC) generation and data modulation. The SPD has similar configuration as the SPE counterpart but using another PM synchronously driven by the complementary code pattern for OC recognition. Simulation investigation and experimental results both show that the code transition, dispersion mismatch between the encoding and decoding side, and the transmission fiber dispersion have detrimental effect on the en/decoding performance. In the experiment, 16-chip, 40-Gchip/s OC pattern and 2.5-Gb/s DPSK data modulation have been simultaneously generated using a single PM. The 2.5-Gb/s DPSK data have been successfully decoded and transmitted over 34 km fiber with BER <; 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-9</sup> for five OCs. The proposed scheme employs similar setup for transmitter and receiver, exhibiting the potential to simplify the architecture of the whole system, and improve the flexibility and confidentiality of OCDMA system.

A full-duplex radio-over-fiber system with differential phase-shift keying signals

We propose a full-duplex radio-over-fiber (ROF) system transmitting 2.5 Gb/s differential phase-shift keying (DPSK) signals with 40GHz optical millimeter-wave as downlink. Meanwhile it can be reused central wavelength as uplink connection for transmitting 2.5 Gb/s on-off keying (OOK) signals. The experimental and simulation results show that the downstream 2.5Gb/s DPSK data and the upstream 2.5Gb/s OOK data can transmit 40km single-mode fiber successfully.

Performance improvement of bandwidth-limited coherent OCDMA system

The performance of an optical code division multiplexing access (OCDMA) system employing the differential phase shift keying (DPSK) data format and turbo code is investigated and simulated. A bandwidth-limited coherent time spreading (TS) OCDMA system is considered. Theoretical results show that performance degradation due to bandwidth limitation could be effectively restrained by the application of the DPSK data format in a coherent OCDMA system, and further performance improvement could be achieved by incorporating turbo coding into the OCDMA system.

Three-chip differential phase-shift keying maximum likelihood sequence estimation for chromatic-dispersion and polarization-mode-dispersion compensation

We propose a novel three-chip differential phase-shift keying (DPSK) maximum likelihood sequence estimation (MLSE) for chromatic-dispersion (CD) and first-order polarization-mode-dispersion (PMD) compensation to extend the transmission reach of the DPSK signal. Such a technique searches the most probable path through the trellis for DPSK data sequence estimation by exploiting the phase difference between not only the adjacent optical bits but also the bits that are one bit slot apart. The proposed scheme significantly outperforms conventional two-chip DPSK MLSE in CD and PMD compensation. We show that the proposed three-chip DPSK MLSE can enhance the CD tolerance of 10 Gbit/s DPSK signal to 2.5 times of that by using two-chip DPSK MLSE and can bound the penalty for 100 ps differential group delay by 1.4 dB.

All-optical phase and amplitude regeneration of return-to-zero differential phase shift keying data

We report a novel implementation of an all-optical rephasing, reshaping, and reamplification differential phase shift keying (DPSK) regenerator. The rephasing is based on converting phase noise into amplitude noise by using an interferometric configuration and then eliminating the amplitude noise by using a semiconductor optical amplifier (SOA). The reshaping is performed using gain competition and gain compression in a saturated SOA. The scheme was tested using 10Gbit/s, 2(23)-1 pseudorandom bit sequence return-to-zero DPSK data. The measurement shows removal of the degraded data error floor with a 6 order-of-magnitude improvement in bit-error rate. The measured negative power penalty is about 4dB. Mathematical analysis shows a reduction in DPSK phase-noise power by half.

Characterization of the performance of optical amplitude-shift keying–differential phase-shift keying orthogonally modulated signals

We analytically investigate the signal performance of orthogonal modulation with slow amplitude-shift keying (ASK) data superimposed upon a high-speed differential phase-shift keying (DPSK) signal. The receiver sensitivities for both the ASK and the demodulated DPSK signals are formulated based on a probability model, and their dependence on the bit rate and the extinction ratio of the ASK data is theoretically investigated. A simple result of analysis of DPSK data performance has been derived. We verified the analytical results by experimental measurements.

An optical network unit for WDM access networks with downstream DPSK and upstream remodulated OOK data using injection-locked FP laser

We investigate the use of optical differential phase-shift keying (DPSK) as the downstream modulation format in a low-cost upstream data remodulation scheme for a wavelength-division multiplexing (WDM)-based passive optical network. A 2.5-Gb/s upstream data transmitter is realized by directly modulating a Fabry-Perot (FP) laser, injection-locked with a 10-Gb/s downstream optical DPSK signal. A simple polarization-offset technique is proposed to largely minimize the induced power penalty.

Simultaneous modulation and fiber-optic transmission of 10-Gb/s baseband and 60-GHz-band radio signals on a single wavelength

A simultaneous modulation and fiber-optic transmission of a 10-Gb/s baseband signal and a 60-GHz RF signal with 155-Mb/s differential-phase-shift-keying (DPSK) data on a single wavelength is investigated. To the authors' knowledge, it is experimentally demonstrated for the first time that both a 10-Gb/s on-off-keying baseband signal and a 60-GHz RF signal with 155-Mb/s DPSK data are simultaneously modulated with a single optical modulator and transmitted over 40-km-long dispersion-shifted fiber (DSF). There exists the received optical power capable of achieving a bit error rate of 10/sup -9/ simultaneously for both the RF and baseband signals. The degradations due to the nonlinearity of the electroabsorption modulator for the baseband and RF signals are also investigated theoretically and clarified numerically.

PN code synchronization effects on narrow-band interference rejection in a direct-sequence spread-spectrum receiver

The impact of imperfect synchronization on the performance of prediction-error interference rejection filters in noncoherent direct-sequence (DS) spread-spectrum communications is considered. Bit-error-rate analysis (BER) analysis (BER) of binary DPSK (differential phase-shift keying) data modulation used in conjunction with direct-sequence spread-spectrum is used as a performance measure. A first-order noncoherent delay-lock loop is used for the pseudonoise (PN) code tracking. Conditional BER results for the DS/DPSK systems for fixed values of the code tracking error are obtained. The average BER of the system is then evaluated by averaging the conditional BER expressions over the probability density function of the code tracking error. Results include the effects of both a single fading tone and a narrowband Gaussian interferer on the overall system performance. Interferer offset frequency is considered in determining the code tracking loop noise as well as the receiver BER. >

Correction to 'Error Performance of Differentially Coherent Detection of Binary DPSK Data Transmission on the Hard-Limiting satellite Channel'

The error performance of differentially coherent detection of a binary differential phase-shift keying (DPSK) system operating over a hard-limiting satellite channel is derived. The main objective is to show the extent of error rate degradation of a DPSK system when a power imbalance exists between the two symbol pulses that are used in a bit decision interval. Consideration is also given to the DPSK error rate performance for the special case of {\em uncorrelated} uplink and {\em correlated} downlink noises at the sampling instants in adjacent time slots. Error probabilities are given as functions of uplink signal-to-noise ratio (SNR) and downlink SNR with different levels of SNR imbalance and different downlink SNR and uplink SNR as parameters, respectively. Our numerical results show that 1) as long as the symbols are equiprobable, the error probability is not dependent upon the downlink noise correlation, regardless of whether there is a power imbalance; 2) error performance is definitely affected by the power imbalance for all cases of symbol distributions; and 3) the error probability does depend upon downlink noise correlation for all levels of power imbalance if the symbol probabilities are not equal.

Error performance of differentially coherent detection of binary DPSK data transmission on the hard-limiting satellite channel

The error performance of differentially coherent detection of a binary differential phase-shift keying (DPSK) system operating over a hard-limiting satellite channel is derived. The main objective is to show the extent of error rate degradation of a DPSK system when a power imbalance exists between the two symbol pulses that are used in a bit decision interval. Consideration is also given to the DPSK error rate performance for the special case of {\em uncorrelated} uplink and {\em correlated} downlink noises at the sampling instants in adjacent time slots. Error probabilities are given as functions of uplink signal-to-noise ratio (SNR) and downlink SNR with different levels of SNR imbalance and different downlink SNR and uplink SNR as parameters, respectively. Our numerical results show that 1) as long as the symbols are equiprobable, the error probability is not dependent upon the downlink noise correlation, regardless of whether there is a power imbalance; 2) error performance is definitely affected by the power imbalance for all cases of symbol distributions; and 3) the error probability does depend upon downlink noise correlation for all levels of power imbalance if the symbol probabilities are not equal.

Effects of a Hard Limiting Repeater on the Performance of a DPSK Data Transmission System

Although the effects of a hard-limiting repeater on coherent phase shift keying (CPSK) data transmission systems have been studied, corresponding effects pertaining to differential phase shift keying (DPSK) systems are yet to be examined. The present paper contains the results of a study on DPSK data detection performance when a hard-limiting repeater is part of the overall data link under consideration, and white Gaussian noise is introduced at the repeater and receiver front ends; the extension to the multi-link system, containing cascaded hard-limiting repeaters, is also included. The results obtained were found to be analogous to those of previous CPSK studies. Specifically, the inclusion of the hard-limiter was generally shown to improve probability of error performance when downlink noise is present. A comparison of present results with those of previous ones for corresponding CPSK systems shows that DPSK is degraded noticeably more by downlink noise than its CPSK counterpart.