| In human society into the information process, people’s needs for communication capacity and communication bandwidth growing。It enables new optical modulation format to get more attention, and quickly play an important role in optical communications.How to limit the error rate of the system within a certain range, to ensure that the optical signals over long distances, high speed and large capacity, reliable transmission, which is the field of optical communication technology has been the goal.In this article, from the principle of optical coupling analyzes the working principle of coupling, modulation and demodulation all the key components. For the characteristics of amplitude modulation, frequency, phase and polarization four kinds of formats, innovative way to carry out research on the theory and simulation CSRZ-FSK-16QAM-APol new modulation formats. And the optical signal is carried out in the form of scalar and vector fibre channel transmission model established, the impact of dispersion and nonlinear effects such as the fibre channel transmission of the signal to be analyzed.The main contents include the following sections:1. Extensive reading of the relevant literature research in the field of optical communications, optical modulation, demodulation research status and fiber channel characteristics, priorities and focus are analyzed; on the light modulation, demodulation, and fibre channel were MATLAB/Simulink simulation research. 2. Starting from the optical coupling principle, it analyzes the working principle of the key components of optical communications. These devices include:fiber optic couplers, phase modulators, Mach-Zehnder modulators, IQ modulators,90°ixers, a polarization diversity receiver and balanced photodetector and the like. A detailed description of the characteristics of each device in the optical communication system.3. After studing the principles of CSRZ-FSK, star16QAM modulation formats and APol generated, it established a mathematical model CSRZ-FSK, star16QAM modulation formats and APol. And integrated ASK, FSK, PSK and APol modulation techniques established on the principle of new modulation formats CSRZ-FSK-16QAM-APol transmitter models.4.The use of sub-fractional Fourier (SSFM) numerical method for nonlinear Schrodinger equation (NLSE),carried out a mathematical description for the transmission loss, chromatic dispersion, polarization mode dispersion and nonlinear effects of fibre channel; By means of MATLAB m-language programming and Simulink simulate, based on the scalar and vector form of mathematical description built fiber channel simulation model.5.By analyzing APol, star-16QAM and CSRZ-FSK signal demodulation principle, according to the working principle of a90°ixer, a polarization diversity receiver and a photoelectric balanced detector, described in detail on the receiver demodulates the baseband signal to restore the entire process.6. After simulation of the process for generation of new CSRZ-FSK-16QAM-APol modulation format optical signal, and it is through the scalar and vector fibre channel transmission, and its reception demodulation, get the signal waveforms and constellation on the key points of the optical fiber communication system, and a bit error rate of signal transmission (BER).And as a basis for in-depth analysis of various performance CSRZ-FSK-16QAM-APol new modulation format of the optical signal. Evaluate the transmission quality and effectiveness of the new modulation format transmitted signals.7.Assessment indicates:CSRZ-FSK-16QAM-APol new modulation format signals to improve its tolerance to fiber channel dispersion and nonlinear effects, improved the bandwidth efficiency and transmission rate and transmission capacity of the system. And making an already very difficult to achieve a single modulation technique to get a good complement to produce a unique effect1+1>2. |
