| The demand of network bandwidth is exploding with the rise of the Internet and data service. For example, the "Light instead of Copper" mode of fixed-line accessing,the blowout of mobile Internet, the rapid growth of video services, cloud computing and the integration of data center transformation, all of the above are the requirements of network bandwidth capacity. The reports of IEEE indicate that lTbps Ethernet wire-speed will be achieved by2015and lOTbps will be available by2020according to the current trends. The existing10G and40G technology cannot meet the huge demand for bandwidth. Therefore the transmissions researches in the world today mostly are about by a single fiber to achieve Tb/s even Pb/s transmission system.At present, the effective way to improve the data transfer rate is the use of higher-order modulation formats combining various multiplexing. Related research realizing Tb/s high-speed optical communication transmission system is the use of multi-QPSK or16QAM modulation formats, such as senior and partial division multiplexing and wavelength division multiplexing technology combined solution. WDM technology utilized in a variety of different wavelengths of the carrier signal (various information) is coupled to the optical fiber for transmission to achieve a high transmission rate, which is now commercially available. In addition to the partial division multiplexing coherent WDM technology combined (Co-WDM), a higher spectrum efficiency can also use orthogonal frequency division multiplexing (OFDM). Core technology of multiplexing is the use of multi-wavelength light source. As we all know, it may cost highly when a number of multi-wavelength lasers is used in system, and also the frequency instability between the lasers are problems, so the frequency-locked stable multi-earner source is needed to overcome the problems. The re-circulating frequency shifter based SSB modulated multi-carrier is a relatively better implementations.In recent years, there are a lot of researches on the stability of multi-carrier sources, including multi-carrier SNR flatness and Analysis of voltage error on IQ modulator, and the optimization for multi-carrier light source performance. However, the characteristics of system devices have impact on the performance of multi-carrier source. Firstly, I/Q modulator is a polarization sensitive device, only the light of a polarization state which is same with the modulated state can be modulated, so the polarization controller can ensure that the signal light is completely IQ modulator modulation, providing a guarantee for the stability of the carrier; Secondly, the optical band-pass filter is used to control the number and range of multi-carrier,whose characteristics impact the stability and flatness of multi-carrier output; Thirdly, the RF IQ modulator drive signal has a direct effect on the signal component and the crosstalk component; Finally, the saturated power of EDFAhas a significant impact on the output of the carriers. Therefore, in-depth study of the impact on the performance of the multi-carrier source due to the device characteristics is essential, which is also a guidance for experimental realization.To solve the above problems, Firstly, this paper studies the advantages of single-sideband modulated multi-carrier; Secondly, this paper analysis the important characteristics of the system components, including the polarization controller, IQ modulators, optical band-pass filters and optical amplifiers; Thirdly, theoretically analyze the performance outputs for multi-carrier due to the characteristics of each devices, including theoretical analysis, numerical simulation and experimental verification. Finally, ensure that the device characteristics required condition is met, and according to the analysis of the stability of SSB multi-carrier based re-circulating frequency shifter, numerical simulation of high quality multi-carrier output is given later; At last, this paper explored a simple application of multi-earner source (optical frequency comb) in measurement technology. The main work consists of following parts:1. Introduce the theoretical knowledge of relevant devices, including the polarization controller, IQ modulators, optical amplifiers, optical band-pass filter, the mathematical model is also given.2. Establish the multi-carrier outputs model considering the effects of polarization controller, IQ modulator, an optical amplifier and an optical filter. The impact due to the polarization characteristics of polarization controller, RF driver of IQ modulator,steepness and depth of optical band-pass filter, and amplification characteristics on multi-carrier output is theoretical analyzed and numerical simulated.3. Establish the stable model of multi-carrier considering the third-order cross-talk, the stable expression of the multi-carrier source is also given.4. Build the experimental system, set the parameters of each device, through theoretical research and numerical simulation stable flat multi-carrier output spectrum is achieved.5. Discuss the measurement application of optical frequency comb on the basis of flat and stable multi-carrier (optical frequency comb) output.In summary, this paper starts from the performance of multi-carrier output, and the impact of performance of multi-carrier source due to the characteristics of system devices is systematically analyzed, including theoretical analysis and numerical simulation, and ultimately through setting each device characteristics, the flat and stable multi-carrier source is achieved. |
PDF Full Text Request