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Wavelength Conversion For The Frame Header And Payload Of NRZ-QPSK Signal

Posted on:2016-05-07Degree:MasterType:Thesis
Country:ChinaCandidate:R WangFull Text:PDF
GTID:2298330467980842Subject:Optical Engineering
Abstract/Summary:PDF Full Text Request
All-optical network (AON) will become a major field of research in the area of future communication networks. AON is made up of core technologies including wavelength division multiplexing (WDM), optical routing, wavelength conversion (WC), optical cross connect (OXC) and optical buffer et al. In WC technology, the wavelength routing and network congestion problems can be solved by utilizing the "virtual wavelength" channels which are established by installing WC device into the cross-node of backbone network. Based on four wave mixing (FWM) in semiconductor optical amplifier (SOA), WC technology has become a research hotspot in the recent years due to its advantages of simple configuration, easy implementation and transparent transmission characteristics.This paper conducts many in-depth theoretical analysis and experimental researches of the WC scheme for QPSK signal based on FWM in SOA.There are a lot of experimental parameters in the FWM scheme based on WC, such as the power of the input signals, bias current of SOA, nonlinear intensity and so on. We have performed analysis of the optimal experimental parameters using simulation software, and investigated how they affect the conversion efficiency. Then the experiment platform which based on the FWM effect for QPSK signal was set up. The experimental results showed that, in addition to the variable parameters mentioned above, the dispersion coefficient of SOA was also an important factor to the conversion efficiency of FWM effect.In order to solve the measurement problem on the dispersion coefficient of SOA, we present a novel method for measuring dispersion coefficient of active devices.With improving the phase-shift method, we experimentally investigated the chromatic dispersion of SOA in detail within the wavelength range from1530nm to1610nm. The simple configuration makes the measurement easy to realize. Experimental results demonstrate that there are three typical dispersion regions, which are abnormal dispersion, flatten dispersion and normal dispersion region, and three zero-dispersion points over the wavelength range of80nm. With increased bias current on SOA, the three zero dispersion points all had a blue shift and the near-zero dispersion regions corresponding became wider. Therefore, the dispersion of SOA can be flexibly adjusted by changing the bias current and input optical power to SOA. So we can adjust the experimental parameters according to requirements of FWM to improve the conversion efficiency and bandwidth.According to the dispersion measurement results, we take wavelength conversion experiment based on SOA-FWM effect under the condition of155mA bias current of SOA and3.5dBm input signal power near the wavelength of1539.6nm, which is one of the zero-dispersion points. The conversion bandwidth has increased3times compared with experimental results in non-zero dispersion regions.
Keywords/Search Tags:SOA, FWM, QPSK, dispersion measurement
PDF Full Text Request
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