Optimum Design for RF-to-Optical Up-Converter in Coherent Optical OFDM Systems
Optimum Design for RF-to-Optical Up-Converter in Coherent Optical OFDM Systems
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DOI：
10.1109/lpt.2007.893582
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发表时间：
2007-04
影响因子：
2.6
通讯作者：
Yan Tang;William Shieh;X. Yi;Robin J. Evans
中科院分区：
文献类型：
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作者：
Yan Tang;William Shieh;X. Yi;Robin J. Evans
在这封信中，我们进行了分析，在相干光OFDM系统中使用光I/Q调制器的RF到光上变频器的优化设计。我们首先推导出封闭形式的表达式的非线性光学I/Q调制器，表示为双音互调产物作为偏置点和调制指数的函数。此外，我们进行了数值模拟，以确定在各种发射机条件下的Q惩罚和多余的调制插入损耗。我们发现，与直接检测系统相比，相干系统的最佳调制器偏置点为π，其中Q惩罚和额外损耗最小
In this letter, we conduct analysis on the optimum design for RF-to-optical up-converter in coherent optical OFDM systems using an optical I/Q modulator. We first derive closed-form expressions for the nonlinearity in the optical I/Q modulator, represented by two-tone intermodulation products as a function of the bias point and modulation index. Additionally, we perform a numerical simulation to identify Q-penalty and the excess modulation insertion loss under various transmitter conditions. We find that in contrast to the direct-detected system, the optimal modulator bias point for the coherent system is pi, where the Q-penalty and excess loss are minimized