| The IP business got a rapid deveopment in recent years, and brought much more pressure on transport networks. The transport network has been continuously developing in the direction of high speed and large capacity. The DWDM system with each wavelength 40Gb/s has been implemented in backbone networks of domestic and oversea network operators. As 100Gb/s transmission technology has developed for several years, some main operators have started the 100Gb/s single-rate and multi-rate mixed trial in current optical transmission networks. In 2010, IEEE, ITU, IETF, OIF standardized the 100Gb/s transmission in progression. With the commercialization of 40Gb/s and the "commercially availability" of 100Gb/s, single-wavelength 400Gb/s transmission technology begins to be interested.The single-wavelength transmission rate has been improved due to the advanced modulation formats evolving from intensity modulation to phase modulation, polarization division multiplex and quadrature modulation. With better spectral efficiency and anti-distortion performance, differential quadrature phase shift keying (DQPSK) and quadrature amplitude modulation (such as 16-QAM) gain high-speed transmission favors.Intelligence is another direction of the development of transport networks. In order to support the large unit IP data services more efficient, the optical transport network (OTN) combining general control plane technology (GMPLS), reconfigurable optical add drop multiplexer (ROADM) and electric field cross-connecter is gradually replacing the traditional SDH optical transmission networks based on DWDM. At present, many manufacturers of optical transmission network elements often adopt different protocols or standards, hence, it results in a line-side interconnection realized by complicated client-side interconnection and a disconnected management layer from one manufacturer to another. To a certain extent, this problem affected the intelligence and robustness of the whole optical transmission networks.Based on the national 863 "high-speed optical fiber communication signal transmission system in the dynamic combination of optical damage equalization technology" project and other projects, this thesis focuses on the following three problems:?optical supervisory channel (OSC) intelligent adapter;?DQPSK modulation Pre-encoding;?16-QAM modulation implementation issues. Specific works are listed as follows:1) Proposed and implemented a universal set of DWDM system optical supervisory channel (OSC) data recording, identification, analysis and adaptation schemes; as the primary researcher, participated in the system design, hardware design, software design and system experiments. After successful OSC analysis and intelligent adaptation to the DWDM network elements of a specific manufacturer, the scheme was proved to be effective, and it also had a versatility of intelligent adaptation to multi-vendor DWDM networks elements. The work has a strong practical value on high-speed optical transmission network elements interconnection and the emergency recovery.2)Investigated the implementation methods of DQPSK pre-coding, and proposed two new structure parallel pre-prefix network algorithms for high-speed pre-coding. We designed and implemented multi-rate electric field DQPSK pre-coding (20Gb/s, 5Gb/s and 4Mb/s). Innovative parallel pipeline method based on Xilinx Virtex 5 FPGA was proposed and implemented, thus breaking the circuit bottleneck of serial pre-coding. With low-speed computing clock (78MHz), high-speed DQPSK pre-coding (20Gb/s) was achieved. The circuit simulation and hardware implementation of multi-rate DQPSK pre-coding proved the feasibility and versatility of the algorithm. Our algorithm can also be applied to 40Gb/s,100Gb/s and higher rate of DQPSK pre-coding.3) Investigated the functional principle of the key optoelectronic devices of high-speed optical transmitter. From the complex domain constellation point of view, we analyzed and explored the corresponding constellation operation rules:rotation, minify-magnify, orthogonal-superposition, and offset-superposition. The results promoted the relationship of constellation realization and optoelectronic devices, which will be helpful to the analysis and implementation of advanced high-order modulation in high-speed transmission networks.4) Proposed the research method that analyzes constellation evolution, then implements advanced modulation combing the constellation operation rules of key components. Based on this method, we proposed three evolution methods of the star 16-QAM constellation and three corresponding implementations, five evolutionary methods of square 16-QAM constellation and six corresponding implementations. These implementations of 448Gb/s transmitter with square 16-QAM constellation were achieved by numerical simulation. From the eye diagram point of view, the time-domain characteristics of the optical signals in different implementations were analyzed. Finally the implementation complexities of different schemes were compared. Our work has a practical significance to the implementation of the 448Gb/s 16-QAM transmitter and more advanced modulation systems.5) Studied the quadrant ambiguity problem in the implementation of QAM transmitter. The differential quadrant coding scheme of the 448Gb/s PM-16QAM transmitter was proposed, and it is good at versatility and transplantation. The work has a certain practical significance. |
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