The Experts below are selected from a list of 14145 Experts worldwide ranked by ideXlab platform
K Kikuchi - One of the best experts on this subject based on the ideXlab platform.
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novel fir filter configuration tolerant to fast phase fluctuations in digital Coherent Receivers for higher order qam signals
Optical Fiber Communication Conference, 2012Co-Authors: Yojiro Mori, Chao Zhang, K KikuchiAbstract:We propose a novel configuration of FIR filters adapted by the decision-directed LMS algorithm in the digital Coherent Receiver. Simulations and experiments show its high tolerance to phase noise and frequency offset for 16-QAM signals.
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characterization of semiconductor laser phase noise and estimation of bit error rate performance with low speed offline digital Coherent Receivers
Optics Express, 2012Co-Authors: K KikuchiAbstract:We develop a systematic method for characterizing semiconductor-laser phase noise, using a low-speed offline digital Coherent Receiver. The field spectrum, the FM-noise spectrum, and the phase-error variance measured with such a Receiver can completely describe phase-noise characteristics of lasers under test. The sampling rate of the digital Coherent Receiver should be much higher than the phase-fluctuation speed. However, 1 GS/s is large enough for most of the single-mode semiconductor lasers. In addition to such phase-noise characterization, interpolating the taken data at 1.25 GS/s to form a data stream at 10 GS/s, we can predict the bit-error rate (BER) performance of multi-level modulated optical signals at 10 Gsymbol/s. The BER degradation due to the phase noise is well explained by the result of the phase-noise measurements.
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characterization of semiconductor laser phase noise with digital Coherent Receivers
Optical Fiber Communication Conference, 2011Co-Authors: K Kikuchi, Koji IgarashiAbstract:We develop a method of characterizing semiconductor-laser phase noise using a digital Coherent Receiver. The field spectrum, FM-noise spectrum, and phase-error variance can completely describe phase-noise characteristics.
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digital Coherent optical communication systems fundamentals and future prospects
IEICE Electronics Express, 2011Co-Authors: K KikuchiAbstract:The recently-developed digital Coherent Receiver enables us to employ a variety of spectrally-efficient modulation formats such as M-ary phase-shift keying (PSK) and quadrature-amplitude modulation (QAM). Moreover, in the digital domain, we can equalize linear transmission impairments, which may stem from group-velocity dispersion (GVD) and polarization-mode dispersion (PMD) of fibers for transmission, because the phase information is preserved after Coherent detection.This paper reviews the history of Coherent optical communications, the principle of Coherent detection, and the concept of the digital Coherent Receiver. After that, we discuss digital signal processing (DSP) for mitigating transmission impairments, Coherent transmission characteristics of multi-level optical signals, and future prospects of Coherent optical communications.
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unrepeated 200 km transmission of 40 gbit s 16 qam signals using digital Coherent Receiver
Optics Express, 2009Co-Authors: Yojiro Mori, Koji Igarashi, Chao Zhang, Kazuhiro Katoh, K KikuchiAbstract:We demonstrate unrepeated 200-km transmission of 40-Gbit/s 16-QAM signals using a digital Coherent Receiver, where the decision-directed carrier-phase estimation is employed. The phase fluctuation is effectively eliminated in the 16-QAM system with such a phase-estimation method, when the linewidth of semiconductor lasers for the transmitter and the local oscillator is 150 kHz. Finite-impulse-response (FIR) filters at the Receiver compensate for 4,000-ps/nm group-velocity dispersion (GVD) of the 200-km-long single-mode fiber and a part of self-phase modulation (SPM) in the digital domain. In spite of the launched power limitation due to SPM, the acceptable bit-error rate performance is obtained owing to high sensitivity of the digital Coherent Receiver.
Seb J. Savory - One of the best experts on this subject based on the ideXlab platform.
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technology requirements for an alamouti coded 100 gb s digital Coherent Receiver using 3 3 couplers for passive optical networks
IEEE Photonics Journal, 2018Co-Authors: Md Saifuddin Faruk, David J Ives, Seb J. SavoryAbstract:© 2017 IEEE. Digital Coherent Receivers employing Alamouti-coding are a promising solution for passive optical networks (PON) with downstream rates of 100 Gb/sλ. To reduce the cost by utilizing high-volume photodiodes designed for 25 Gb/s data-center applications, we consider 28-Gbaud 16-QAM modulation format detected with a single-polarization Coherent Receiver based on a 3 × 3 coupler with single-ended detection. We investigate two alternative configurations: first, a Receiver with a symmetric 3 × 3 coupler and second, an IQ coupler (asymmetric 3 × 3 coupler) with Alamouti-coding based polarization diversity. In this paper, we present a detailed investigation as to the feasibility of both the Receivers for a wide range of parameters including quantization noise, relative intensity noise, I/Q mismatch, etc. It is found that such Receivers can be realized with commercially available components. We also quantify the penalty associated with nonideal components to allow for lower cost designs with reduced specifications suitable for access applications. In addition, we present the adaptive DSP algorithms required to recover data for a single-carrier Alamouti-coded signal. Considering both linear and nonlinear impairments, a power budget of 36.4 dB and 33.1 dB is found at BER of 3.8 ×, 10-3 for a Receiver with symmetric 3 × 3 coupler and IQ coupler, respectively, and thereby proving their applicability as Receivers for 100 Gb/sλ PON.
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polarization insensitive single balanced photodiode Coherent Receiver for long reach wdm pon s
Journal of Lightwave Technology, 2016Co-Authors: Sezer M Erkilinc, Domanic Lavery, Benn C Thomsen, R I Killey, P Bayvel, Kai Shi, Seb J. SavoryAbstract:In an access network based on a passive optical network architecture, Coherent detection is attractive since it allows for high Receiver sensitivity coupled with inherent frequency selectivity. Nevertheless, solutions employed in core networks are prohibitively complex and costly, requiring the optical complexity of the Coherent Receivers to be reduced to make them feasible for access networks. For monolithic integration, a key challenge is posed by the polarization beam splitter (PBS). If, however, the PBS is removed, the Receiver needs to be redesigned to be insensitive to the incoming polarization state of the received signal. In this paper, we experimentally demonstrate a polarization-insensitive (i.e., polarization-independent) Coherent Receiver for the optical network unit in passive optical networks (PONs). The Receiver consists of only a 3-dB coupler and a single-balanced photodiode such that the complexity is comparable to a direct detection Receiver. The proposed cost-effective Coherent Receiver is implemented by using the Alamouti polarization-time block coding scheme combined with heterodyne detection. To verify the technique, the Alamouti-coded orthogonal frequency division multiplexing (OFDM) signal is rotated over the full Poincare sphere. Compared to the dual-polarization-OFDM signal operating at a net bit rate of 10 Gb/s per polarization (a gross bit rate of 10.7 Gb/s including a 7% FEC overhead), only a 0.6 dB sensitivity degradation is observed. The sensitivity at the FEC threshold, assumed to be $4\times 10^{-3}$ , is measured to be $-$ 41.5 dBm (56 photons-per-bit) on a 25-GHz grid. Following this, different channel spacings are investigated and the signal is transmitted over 80 km of standard single-mode fiber in a long-reach wavelength division multiplexed PON system. The loss budgets are found to be 43.0 and 42.8 dB for 50- and 25-GHz grids, respectively.
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digital Coherent technology for long reach optical access
Optical Fiber Communication Conference, 2014Co-Authors: Domanic Lavery, Seb J. SavoryAbstract:This semi-tutorial paper outlines the potential advantages afforded by digital Coherent Receivers in long-reach optical access networks. Low complexity DSP algorithms are discussed which relax the optical complexity requirements of a Coherent Receiver. © OSA 2014.
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widely tunable burst mode digital Coherent Receiver with fast reconfiguration time for 112 gb s dp qpsk wdm networks
Journal of Lightwave Technology, 2012Co-Authors: Robert Maher, Seb J. Savory, David S Millar, Benn C ThomsenAbstract:A widely tunable burst mode digital Coherent Receiver is implemented in a 112 Gb/s DP-QPSK WDM system. The Receiver performance is validated in a 24-channel WDM test-bed using a commercially available DS-DBR laser as the local oscillator. It is demonstrated that the wavelength tunable laser can switch to any one of the 24-channels in less than 130 ns, thus enabling the dynamic reception of 5 μ s optical bursts. The performance of the DS-DBR local oscillator laser is commensurate with burst mode Coherent reception when differential decoding is employed and the parallel DSP implementation does not impair the polarization and frequency tracking performance of a digital Coherent Receiver under burst mode operation. The worst case reconfiguration time of the burst mode Receiver, which is a combination of the laser switching time and the CMA convergence time, is less than 410 ns when switching from a single channel to any other channel in the WDM grid. It is shown that the variation in reconfiguration time is dependent on the convergence time of the CMA equalizer, which is adversely affected by certain input states of polarization.
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a long reach ultra dense 10 gbit s wdm pon using a digital Coherent Receiver
Optics Express, 2010Co-Authors: Domanic Lavery, Maria Ionescu, Sergejs Makovejs, E Torrengo, Seb J. SavoryAbstract:We investigate the impact of channel spacing and nonlinear transmission over 120 km of standard single mode fiber for a 10 Gbit/s long-reach wavelength division multiplexed passive optical network (WDM-PON). We employed polarization division multiplexed quadrature phase shift keying (PDM-QPSK), which allowed data transmission at 3.125 GBaud, including a 25% overhead for forward error correction. To receive this spectrally efficient modulation format, a digital Coherent Receiver was employed, allowing for both frequency selectivity and an increased sensitivity of -45 dBm (25 photons/bit).We investigated a channel spacing as low as 5 GHz, for which the loss budget was 48.6 dB, increasing to 54.0 dB for a 50 GHz grid.
Josef Blanz - One of the best experts on this subject based on the ideXlab platform.
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joint detection with Coherent Receiver antenna diversity in cdma mobile radio systems
IEEE Transactions on Vehicular Technology, 1995Co-Authors: Peter Jung, Josef BlanzAbstract:In code division multiple access (CDMA) mobile radio systems, both intersymbol interference and multiple access interference arise which can be combated by using either elaborate optimum or favorable suboptimum joint detection (JD) techniques. Furthermore, the time variation of the radio channels leads to degradations of the Receiver performance. These degradations can be reduced by applying diversity techniques. Using Coherent Receiver antenna diversity (CRAD) is especially attractive because only the signal processing at the Receiver must be modified. In the present paper, the application of CRAD to the more critical uplink of CDMA mobile radio systems with suboptimum JD techniques is investigated for maximal-ratio combining. The authors study six different suboptimum JD techniques based on decorrelating matched filtering, Gauss-Markov estimation, and minimum mean square error estimation with and without decision feedback. These six suboptimum JD techniques which are well-known for single antenna Receivers are extended for the application to CRAD. A main concern of the paper is the determining of the SNR performance of the presented JD techniques for CRAD and the achievable average uncoded bit error probabilities for the transmission over rural area, typical urban and bad urban mobile radio channels are determined.
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performance of a cellular hybrid c tdma mobile radio system applying joint detection and Coherent Receiver antenna diversity
IEEE Journal on Selected Areas in Communications, 1994Co-Authors: Josef Blanz, Anja Klein, M Nasshan, A SteilAbstract:For future mobile radio systems, an appropriately chosen multiple access technique is a critical issue. Multiple access techniques presently under discussion are code division multiple access (CDMA), time division multiple access (TDMA), and hybrids of both. In the paper, a hybrid C/TDMA system using joint detection (JD-C/TDMA) with Coherent Receiver antenna diversity (CRAD) at the base station (BS) Receiver is proposed. Some attractive features of the JD-C/TDMA system are the possibility to flexibly offer voice and data services with different bit rates, soft capacity, inherent frequency and interferer diversity, and high system capacity due to JD. Furthermore, due to JD, a cluster size equal to 1 can be realized without needing soft handover. The single cell E/sub b//N/sub 0/ performance and the interference situation in a cellular environment of the uplink of a JD-C/TDMA mobile radio system with CRAD is investigated in detail. It is shown that the cellular spectrum efficiency is remarkably high, taking values up to 0.2 bit/s/Hz/BS in the uplink, depending on the actual transmission conditions. >
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performance of a cellular hybrid c tdma mobile radio system applying joint detection and Coherent Receiver antenna diversity
MILCOM '93, 1994Co-Authors: Josef Blanz, Anja Klein, M Nasshan, A SteilAbstract:For future mobile radio systems, an appropriately chosen multiple access technique is a critical issue. Multiple access techniques presently under discussion are code division multiple access (CDMA), time division multiple access (TDMA), and hybrids of both. In this paper, a hybrid C/TDMA system using joint detection (JD-C/TDMA) with Coherent Receiver antenna diversity (CRAD) at the base station (BS) Receiver is proposed. Some attractive features of the JD-C/TDMA system are the possibility to flexibly offer voice and data services with different bit rates, soft capacity, inherent frequency and interferer diversity, and high system capacity due to JD. Furthermore, due to JD, a cluster size equal to 1 can be realized without needing soft handover
M Nasshan - One of the best experts on this subject based on the ideXlab platform.
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results on turbo codes for speech transmission in a joint detection cdma mobile radio system with Coherent Receiver antenna diversity
IEEE Transactions on Vehicular Technology, 1997Co-Authors: Peter Jung, M NasshanAbstract:Turbo-codes which are applicable to speech transmission in digital mobile radio systems are treated. Three turbo-codes of different complexity are presented. The proposed turbo-codes are suitable for the application to speech transmission in the joint detection code-division multiple access (JD-CDMA) mobile radio system with Coherent Receiver antenna diversity (CRAD) which are described concisely. The performance of the designed turbo-codes in terms of bit and frame error rates are shown in the case of additive white Gaussian noise (AWGN) channels, flat Rayleigh fading channels, and in the uplink of the aforementioned JD-CDMA mobile radio system.
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performance of a cellular hybrid c tdma mobile radio system applying joint detection and Coherent Receiver antenna diversity
IEEE Journal on Selected Areas in Communications, 1994Co-Authors: Josef Blanz, Anja Klein, M Nasshan, A SteilAbstract:For future mobile radio systems, an appropriately chosen multiple access technique is a critical issue. Multiple access techniques presently under discussion are code division multiple access (CDMA), time division multiple access (TDMA), and hybrids of both. In the paper, a hybrid C/TDMA system using joint detection (JD-C/TDMA) with Coherent Receiver antenna diversity (CRAD) at the base station (BS) Receiver is proposed. Some attractive features of the JD-C/TDMA system are the possibility to flexibly offer voice and data services with different bit rates, soft capacity, inherent frequency and interferer diversity, and high system capacity due to JD. Furthermore, due to JD, a cluster size equal to 1 can be realized without needing soft handover. The single cell E/sub b//N/sub 0/ performance and the interference situation in a cellular environment of the uplink of a JD-C/TDMA mobile radio system with CRAD is investigated in detail. It is shown that the cellular spectrum efficiency is remarkably high, taking values up to 0.2 bit/s/Hz/BS in the uplink, depending on the actual transmission conditions. >
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performance of a cellular hybrid c tdma mobile radio system applying joint detection and Coherent Receiver antenna diversity
MILCOM '93, 1994Co-Authors: Josef Blanz, Anja Klein, M Nasshan, A SteilAbstract:For future mobile radio systems, an appropriately chosen multiple access technique is a critical issue. Multiple access techniques presently under discussion are code division multiple access (CDMA), time division multiple access (TDMA), and hybrids of both. In this paper, a hybrid C/TDMA system using joint detection (JD-C/TDMA) with Coherent Receiver antenna diversity (CRAD) at the base station (BS) Receiver is proposed. Some attractive features of the JD-C/TDMA system are the possibility to flexibly offer voice and data services with different bit rates, soft capacity, inherent frequency and interferer diversity, and high system capacity due to JD. Furthermore, due to JD, a cluster size equal to 1 can be realized without needing soft handover
P Bayvel - One of the best experts on this subject based on the ideXlab platform.
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a 32x10 gb s olt using a single ultra wide bandwidth dual local oscillator Coherent Receiver
IEEE Photonics Conference, 2017Co-Authors: Domanic Lavery, Lidia Galdino, Zhixin Liu, Sezer Erkilinc, P BayvelAbstract:Detection of a 32×10 Gb/s channel UDWDM-PON in a single, wide bandwidth Coherent Receiver is enabled using two, frequency-separated, local oscillator lasers. The preservation of Receiver linearity is demonstrated through digital dispersion compensation and channel isolation after 80 km transmission.
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polarization insensitive single balanced photodiode Coherent Receiver for long reach wdm pon s
Journal of Lightwave Technology, 2016Co-Authors: Sezer M Erkilinc, Domanic Lavery, Benn C Thomsen, R I Killey, P Bayvel, Kai Shi, Seb J. SavoryAbstract:In an access network based on a passive optical network architecture, Coherent detection is attractive since it allows for high Receiver sensitivity coupled with inherent frequency selectivity. Nevertheless, solutions employed in core networks are prohibitively complex and costly, requiring the optical complexity of the Coherent Receivers to be reduced to make them feasible for access networks. For monolithic integration, a key challenge is posed by the polarization beam splitter (PBS). If, however, the PBS is removed, the Receiver needs to be redesigned to be insensitive to the incoming polarization state of the received signal. In this paper, we experimentally demonstrate a polarization-insensitive (i.e., polarization-independent) Coherent Receiver for the optical network unit in passive optical networks (PONs). The Receiver consists of only a 3-dB coupler and a single-balanced photodiode such that the complexity is comparable to a direct detection Receiver. The proposed cost-effective Coherent Receiver is implemented by using the Alamouti polarization-time block coding scheme combined with heterodyne detection. To verify the technique, the Alamouti-coded orthogonal frequency division multiplexing (OFDM) signal is rotated over the full Poincare sphere. Compared to the dual-polarization-OFDM signal operating at a net bit rate of 10 Gb/s per polarization (a gross bit rate of 10.7 Gb/s including a 7% FEC overhead), only a 0.6 dB sensitivity degradation is observed. The sensitivity at the FEC threshold, assumed to be $4\times 10^{-3}$ , is measured to be $-$ 41.5 dBm (56 photons-per-bit) on a 25-GHz grid. Following this, different channel spacings are investigated and the signal is transmitted over 80 km of standard single-mode fiber in a long-reach wavelength division multiplexed PON system. The loss budgets are found to be 43.0 and 42.8 dB for 50- and 25-GHz grids, respectively.
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transmission of 42 8gbit s polarization multiplexed nrz qpsk over 6400km of standard fiber with no optical dispersion compensation
Optical Fiber Communication Conference, 2007Co-Authors: Seb J. Savory, G Gavioli, R I Killey, P BayvelAbstract:We report the longest reach achieved for a 42.8 Gbit/s system on standard fiber with no optical dispersion compensation. Using a digital Coherent Receiver a record total dispersion of 107,424 ps/nm was compensated with 1.2 dB OSNR penalty.
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electronic compensation of chromatic dispersion using a digital Coherent Receiver
Optics Express, 2007Co-Authors: Seb J. Savory, G Gavioli, R I Killey, P BayvelAbstract:Digital signal processing (DSP) combined with a phase and polarization diverse Coherent Receiver is a promising technology for future optical networks. Not only can the DSP be used to remove the need for dynamic polarization control, but also it may be utilized to compensate for nonlinear and linear transmission impairments. In this paper we present results of a 42.8Gbit/s nonlinear transmission experiment, using polarization multiplexed QPSK data at 10.7GBaud, with 4 bits per symbol. The digital Coherent Receiver allows 107,424 ps/nm of chromatic dispersion to be compensated digitally after transmission over 6400km of standard single mode fiber.
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transmission of 42 8gbit s polarization multiplexed nrz qpsk over 6400km of standard fiber with no optical dispersion compensation
In: Optics InfoBase Conference Papers. (2007), 2007Co-Authors: Seb J. Savory, G Gavioli, R I Killey, P BayvelAbstract:We report the longest reach achieved for a 42.8Gbit/s system on standard fiber with no optical dispersion compensation. Using a digital Coherent Receiver a record total dispersion of 107,424ps/nm was compensated with 1.2dB OSNR penalty. ©2006 Optical Society of America.