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Study On All-optical Signal Regeneration Systems In Ultra-fast Optical Networks

Posted on:2016-02-14Degree:DoctorType:Dissertation
Country:ChinaCandidate:H FengFull Text:PDF
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This paper is expanded based on the National Natural Science Foundation of China—— "distributed network transmission speed laser constellation Theory and Technology"(NSFC No.61231012).In the modern era with the amount of data in the exponential growth, and the demand for information as well as the rapid development of information technology, to build the ultra-high-speed, high-capacity all-optical network is imperative. However, for very high speed optical network, due to the channel crosstalk attenuation, chromatic dispersion, and a variety of nonlinear effects in high-speed long-distance transmission, optical signals is severely damaged and distorted by the long-haul optical signal transmission. Therefore, optical signal regeneration relay technology will be an effective means to solve this problem.Due to the restrictions caused by "electronic speed bottleneck" in the bulky optoelectronic devices, optoelectronic hybrid relay based on the traditional "optical-electrical- optical"(OEO) function can not meet the regeneration needs of the ultrahigh-speed transmission distorted optical signals. Compared with the traditional OEO relay, all-optical relay with low power consumption, small size, and without signal OE-O conversion, is relatively transparent to the signal rate and modulation pattern. So take all-optical means for damaged optical signal regeneration can effectively solve the problem of optical signal attenuation and distortion caused by long-distance transmission link, which is promising and will be the key technology of the future ultrafast all-optical network.In this paper, to solve the signal regeneration problems in ultra-high-speed-largecapacity networks, we take a series of research in all-optical 1R(Re-amplification) regeneration, all-optical 2R(Re-amplification, Re-shaping) regeneration, and alloptical 3R(Re-amplification, Re-shaping, Re-timing). Through simulation and experimental study of all-optical regeneration system in different means, we have achieved amount of results as following:1. We proposed a pre-amplification mechanism based on cascaded erbium-doped fiber amplifier with forward pump to achieve low-noise high-gain amplification of weak signals, as named all-optical 1R regeneration. It is pointed out that, compared with the traditional scheme, the all-optical 1R regeneration scheme we proposed can effectively suppress the spontaneous emission noise in erbium-doped fiber amplifier, and achieve high receiver sensitivity, low noise figure, high signal gain of weak signals. It is a sound way to realize signal amplification with low noise and high gain, which can be utilized directly in the direct-detection space optical communication systems for all-optical 1R regeneration of weak signals.2. We proposed some methods for all-optical wavelength conversion based signal 2R regeneration utilizing cross-gain modulation, self-phase modulation, cross-phase modulation, four-wave mixing and other third-order nonlinear optical effects in the high-nonlinearity mediums. The research results indicate that our final scheme employing degenerate four-wave-mixing polarization-diversity structure have the ability to achieve all-optical 2R regeneration with a wide wavelength regeneration range, high conversion efficiency, and transparency to signal modulation format and signal bit rate, furthermore, the scheme is polarization insensitive. Therefore, our final 2R regeneration scheme based on degenerate four-wave-mixing polarization-diversity structure can be widely used in all-optical 2R regeneration relay, the wavelengthaddressed all-optical switches, and the multicast signal multiplexer.3. We proposed a sound clock recovery method to extract synchronous all-optical clock from the transmission signal, which is based on an injection mode-locked lasers with cross-gain modulation in semiconductor optical amplifier. It is emphasized that by utilizing a backward injection continuous wave as the assist light to speed up the carrier lifetime, the pattern effect induced by long carrier recovery time of SOA can be effectively overcome. Using this scheme, 10 GHz synchronous clock pulses are recovered from the transmission 10 Gbps RZ-OOK signals with good quality of low timing jitter, low amplitude fluctuation, and short pulse duration. In further, the proposed optical clock recovery scheme can be effectively used in the all-optical synchronous extraction of RZ signals, which is a key technology of retiming in the optical decision gate.4. Based on the research conclusion of all-optical 2R regeneration, we proposed an all-optical decision gate scheme utilizing the degenerate four-wave-mixing polarization-diversity structure. Combined with the all-optical clock recovery technology, all-optical 3R regeneration signal can be achieved with re-amplification, re-shaping and re-timing. It indicates that the all-optical 3R regeneration scheme can be effectively employed in the single-wavelength ultrafast optical time-division multiplexing systems and optical time-division multiplexing and dense wavelengthdivision multiplexing hybrid high-capacity optical networks to achieve re-amplification, re-shaping and re-timing of impaired transmission RZ signals.5. We firstly proposed a multi-wavelength ultrashort-pulse mode-locked fiber laser structure based on modelocking utilizing cross-gain modulation in semiconductor optical amplifier combined with regeneration utilizing four-wave mixing in highnonlinearity fibers. The experimental results show that our proposed scheme for generation of multi-wavelength ultrashort mode-locked pulse trains has great research value and can be applied as the potential pulse carriers in the integration of dense wavelength-division multiplexing and optical time-division multiplexing network, which is a sound and key technology to achieve ultra-high-speed, high-capacity alloptical networks.6. We proposed an all-optical signal regeneration system structure in the ultrahigh-speed large-capacity optical networks. By setting up experiments to verify the general applicability, program feasibility and technical superiority of our proposed alloptical regeneration systems, it is pointed out that our regeneration systems has practical use and is promising in future networks.
Keywords/Search Tags:ultrafast all-optical networks, time division multiplexing, all-optical signal regeneration, all-optical wavelength conversion, multi-channel multicast, optical switching, active mode-locked laser, all-optical clock recovery, all-optical decision gate
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