Digital power division multiplexed DD-OFDM using fundamental mode transmission in few-mode fiber.
TL;DR: DPDM transmission with DD-OFDM over few-mode fiber offers doubling of both split ratio and spectral efficiency over single-mode fibers when used for passive optical networks, and the constituent signals of the DPDM scheme have similar nonlinear thresholds compared to the DD- OFDM signal with higher-order modulation.
Abstract: We experimentally demonstrate fundamental mode transmission of digital power division multiplexed direct detection - orthogonal frequency division multiplexed (DD-OFDM) signal at 25.3 Gbps in 6.5 GHz bandwidth through a 5.3 km few-mode fiber. We compare the performance of a two-channel digital power division multiplexed (DPDM) signal with DD-OFDM of higher modulation format with the same spectral efficiency in both linear and nonlinear regimes of operation. In the linear regime, the mean bit error rate performance of the two-channel DPDM signal performance is comparable to the DD-OFDM signal with higher-order modulation. In the nonlinear regime, both the constituent signals of the DPDM scheme have similar nonlinear thresholds compared to the DD-OFDM signal with higher-order modulation. DPDM transmission with DD-OFDM over few-mode fiber offers doubling of both split ratio and spectral efficiency over single-mode fibers when used for passive optical networks.
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TL;DR: In this paper , the authors proposed a chaotic power division multiplexing (CPDM) for secure optical multiple access (OMA), which can not only improve spectral efficiency and the user number, but also ensure information security of the users by implementing chaotic encryption on the physical layer.
Abstract: This paper proposes a novel chaotic power division multiplexing (CPDM) for secure optical multiple access. The proposed CPDM can not only improve spectral efficiency and the user number by multiplexing spectrally overlaid OFDM signals at different power ratio, but also ensure the information security of the users by implementing chaotic encryption on the physical layer. The key space of the encryption scheme is up to ${10^{98}}$
4 citations
01 Jan 2008
TL;DR: In this article, the authors proposed a mode-field matched center-launching technique by fusion-splicing a single-mode fiber (SMF) pigtailed transmitter to the MMF, where the splicing condition is optimized to expand the core of SMF slightly so that it can match the mode field distribution of the fundamental mode of MMF.
Abstract: We report that the center-launching technique can be improved to selectively excite the fundamental mode of multimode fiber (MMF). This ldquomode-field matchedrdquo center-launching technique enables us to excite only the fundamental mode in the MMF and, consequently, avoid the inherent limitations imposed by the differential mode delay. We realize this mode-field matched center-launching technique simply by fusion-splicing a single-mode fiber (SMF) pigtailed transmitter to the MMF. The splicing condition is optimized to expand the core of SMF slightly so that it can match the mode field distribution of the fundamental mode of MMF. The results show that, by using this launching technique, we can achieve the transmission characteristics similar to SMF and drastically increase the bandwidth-distance product of MMF. For demonstrations, we have successfully transmitted 10- and 40-Gb/s signals over 12.2 and 3.7 km of MMF, respectively, without using any dispersion compensation techniques. We have also evaluated the robustness of the MMF link implemented by using the proposed launching technique against the mechanical perturbations such as the lateral offset between fiber connectors, fiber bending, and fiber shaking.
4 citations
TL;DR: The proposed security-enhanced power divisionmultiplexing space division multiplexing passive optical network (SPDM-SDM-PON) support multi-threading and multi-functions, showing a great potential to be applied in the future telecommunication systems.
Abstract: We propose a novel security-enhanced power division multiplexing (SPDM) optical non-orthogonal multiple access scheme in conjunction with seven-core optical fiber in this paper. This scheme could improve the security of data transmission at the physical layer and the split ratio of the access network, ensuring more users can be served at the same time. Additionally, multiple signals can be superimposed in the digital domain, leading to a significant improvement in spectral efficiency. We have further experimentally demonstrated the transmission of 47.25 Gb/s SPDM orthogonal frequency division multiplexing (OFDM) signals in a 2 km seven-core fiber system. The experimental results confirm that our scheme can increase the number of access users by 14 times without influencing the privacy of different users. It is worth mentioning the signal encryption method based on amino acids combine with extended zigzag is proposed for the first time as we know. Meanwhile, the key space reaches 10182, indicating that the data transmission process can be effectively protected from the attack of stealers. The proposed security-enhanced power division multiplexing space division multiplexing passive optical network (SPDM-SDM-PON) support multi-threading and multi-functions, showing a great potential to be applied in the future telecommunication systems.
TL;DR: In this article , the authors proposed a security system that combines PDM and SDM and is based on the flexible configuration of multi-channel keys, which can accommodate a variety of rate and security needs.
Abstract: The purpose of this study is to present a security system that combines PDM and SDM and is based on the flexible configuration of multi-channel keys. The proposed system will utilize three distinct approaches to accommodate a variety of rate and security needs. In order to enhance resource use and fulfill rate requirements, the three-channel PD-OFDM has been proposed. Key co-transmission schemes containing two sub-schemes for deal with different levels of encryption. Experimental results show that the proposed system can transmit 126.88 Gb/s OFDM signals in the unencrypted three-channel PD-OFDM scheme, 95.16 Gb/s OFDM signals in the one-channel key scheme and 63.44 Gb/s OFDM signals in the two-channel key scheme across 2 km 7-core fiber. Both security and speed requirements are considered to achieve a flexible system configuration.
DOI•
TL;DR: In this article , the authors proposed a security system that combines PDM and SDM and is based on the flexible configuration of multi-channel keys, which can accommodate a variety of rate and security needs.
Abstract: The purpose of this study is to present a security system that combines PDM and SDM and is based on the flexible configuration of multi-channel keys. The proposed system will utilize three distinct approaches to accommodate a variety of rate and security needs. In order to enhance resource use and fulfill rate requirements, the three-channel PD-OFDM has been proposed. Key co-transmission schemes containing two sub-schemes for deal with different levels of encryption. Experimental results show that the proposed system can transmit 126.88 Gb/s OFDM signals in the unencrypted three-channel PD-OFDM scheme, 95.16 Gb/s OFDM signals in the one-channel key scheme and 63.44 Gb/s OFDM signals in the two-channel key scheme across 2 km 7-core fiber. Both security and speed requirements are considered to achieve a flexible system configuration.
References
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TL;DR: This paper comprehensively surveys the recent progress of NOMA in 5G systems, reviewing the state-of-the-art capacity analysis, power allocation strategies, user fairness, and user-pairing schemes in NomA.
Abstract: Non-orthogonal multiple access (NOMA) is one of the promising radio access techniques for performance enhancement in next-generation cellular communications. Compared to orthogonal frequency division multiple access, which is a well-known high-capacity orthogonal multiple access technique, NOMA offers a set of desirable benefits, including greater spectrum efficiency. There are different types of NOMA techniques, including power-domain and code-domain. This paper primarily focuses on power-domain NOMA that utilizes superposition coding at the transmitter and successive interference cancellation at the receiver. Various researchers have demonstrated that NOMA can be used effectively to meet both network-level and user-experienced data rate requirements of fifth-generation (5G) technologies. From that perspective, this paper comprehensively surveys the recent progress of NOMA in 5G systems, reviewing the state-of-the-art capacity analysis, power allocation strategies, user fairness, and user-pairing schemes in NOMA. In addition, this paper discusses how NOMA performs when it is integrated with various proven wireless communications techniques, such as cooperative communications, multiple-input multiple-output, beamforming, space-time coding, and network coding among others. Furthermore, this paper discusses several important issues on NOMA implementation and provides some avenues for future research.
1,406 citations
TL;DR: In this paper, the authors comprehensively survey the recent progress of NOMA in 5G systems, reviewing the state-of-the-art capacity analysis, power allocation strategies, user fairness, and user-pairing schemes in NOMAs.
Abstract: Non-orthogonal multiple access (NOMA) is one of the promising radio access techniques for performance enhancement in next-generation cellular communications. Compared to orthogonal frequency division multiple access (OFDMA), which is a well-known high-capacity orthogonal multiple access (OMA) technique, NOMA offers a set of desirable benefits, including greater spectrum efficiency. There are different types of NOMA techniques, including power-domain and code-domain. This paper primarily focuses on power-domain NOMA that utilizes superposition coding (SC) at the transmitter and successive interference cancellation (SIC) at the receiver. Various researchers have demonstrated that NOMA can be used effectively to meet both network-level and user-experienced data rate requirements of fifth-generation (5G) technologies. From that perspective, this paper comprehensively surveys the recent progress of NOMA in 5G systems, reviewing the state-of-the-art capacity analysis, power allocation strategies, user fairness, and user-pairing schemes in NOMA. In addition, this paper discusses how NOMA performs when it is integrated with various proven wireless communications techniques, such as cooperative communications, multiple input multiple output (MIMO), beamforming, space time coding, and network coding, among others. Furthermore, this paper discusses several important issues on NOMA implementation and provides some avenues for future research.
879 citations
TL;DR: General OFDM principles, including orthogonality, cyclic prefix use, frequency-domain equalization, and multiuser OFDMA are summarized, followed by an overview of various optical OFDM(A) transceiver architectures for next-generation PON.
Abstract: In this tutorial overview, the principles, advantages, challenges, and practical requirements of optical orthogonal frequency division multiplexing (OFDM)-based optical access are presented, with an emphasis on orthogonal frequency division multiple access (OFDMA) for application in next-generation passive optical networks (PON). General OFDM principles, including orthogonality, cyclic prefix use, frequency-domain equalization, and multiuser OFDMA are summarized, followed by an overview of various optical OFDM(A) transceiver architectures for next-generation PON. Functional requirements are outlined for high-speed digital signal processors (DSP) and data converters in OFDMA-PON. A techno-economic outlook for such a “software-defined,” DSP-based optical access platform is also provided.
511 citations
TL;DR: Few-mode fibers (FMFs) are demonstrated as a good compromise since they are sufficiently resistant to mode coupling compared to standard multimode fibers but they still can have large core diameters compared to single-mode fiber.
Abstract: Using multimode fibers for long-haul transmission is proposed and demonstrated experimentally. In particular few-mode fibers (FMFs) are demonstrated as a good compromise since they are sufficiently resistant to mode coupling compared to standard multimode fibers but they still can have large core diameters compared to single-mode fibers. As a result these fibers can have significantly less nonlinearity and at the same time they can have the same performance as single-mode fibers in terms of dispersion and loss. In the absence of mode coupling it is possible to use these fibers in the single-mode operation where all the data is carried in only one of the spatial modes throughout the fiber. It is shown experimentally that the single-mode operation is achieved simply by splicing single-mode fibers to both ends of a 35-km-long dual-mode fiber at 1310 nm. After 35 km of transmission, no modal dispersion or excess loss was observed. Finally the same fiber is placed in a recirculating loop and 3 WDM channels each carrying 6 Gb/s BPSK data were transmitted through 1050 km of the few-mode fiber without modal dispersion.
174 citations
TL;DR: In this article, the authors proposed a scheme in which the bandwidth-distance product of a multimode fiber is extended, so that it can nearly support the transmission rate of single-mode systems, based on selective launching of lower order modes into the fiber at the transmitting end and on filtering out at the receiver the fraction of the energy that was coupled into the higher order modes throughout the propagation in the multimodal fiber.
Abstract: A scheme in which the bandwidth-distance product of a multimode fiber is extended, so that it can nearly support the transmission rate of single-mode systems, is studied. It is based on selective launching of lower order modes into the fiber at the transmitting end and on filtering out at the receiver the fraction of the energy that was coupled into the higher order modes throughout the propagation in the multimode fiber. The power penalty and the dispersion performance of the scheme are investigated. In particular, it is shown that the scheme carries about 6.5 dB penalty, and doubling of the bandwidth*distance value is demonstrated. The effect of splices on the performance is also presented. It is envisioned that this approach may be used to upgrade existing multimode systems without the need for rewiring. For example, it can be used to replace the FDDI (fiber distributed data interface) installations in future high-speed networks, when transmission rates increase from megabits per second to gigabits per second. >
127 citations