CAJ | 학술논문

在直接检测光正交频分复用(DD-OFDM)系统中,同相/正交相(IQ)不平衡造成严重的性能下降.我们搭建了两个分别实现双边带(DSB)和单边带(SSB)调制的背靠背DD-OFDM系统,并依据差错向量幅度(EVM)和符号差错率(SER)分析比较了上述两系统对IQ不平衡的容忍度.结果表明,在背靠背情形下,DSB系统比SSB系统对IQ不平衡的容忍度要大.我们还搭建了两个传输距离均为40 km的DD-OFDM系统,分别实现了DSB信号和SSB信号的传输,同样依据EVM和SER分析比较了这两个系统对IQ不平衡的容忍度.结果表明,在传输距离为40 km的情况下,SSB调制比DSB调制更能增强DD-OFDM系统在传输信号时对IQ不平衡的容忍度.
재직접검측광정교빈분복용(DD-OFDM)계통중,동상/정교상(IQ)불평형조성엄중적성능하강.아문탑건료량개분별실현쌍변대(DSB)화단변대(SSB)조제적배고배DD-OFDM계통,병의거차착향량폭도(EVM)화부호차착솔(SER)분석비교료상술량계통대IQ불평형적용인도.결과표명,재배고배정형하,DSB계통비SSB계통대IQ불평형적용인도요대.아문환탑건료량개전수거리균위40 km적DD-OFDM계통,분별실현료DSB신호화SSB신호적전수,동양의거EVM화SER분석비교료저량개계통대IQ불평형적용인도.결과표명,재전수거리위40 km적정황하,SSB조제비DSB조제경능증강DD-OFDM계통재전수신호시대IQ불평형적용인도.
In-phase/Quadrature-phase(IQ)imbalance can result in severe performance degradation in optical Direct-detection Orthogonai-frequency-division-multiplexing(DD-OFDM)systems.We build two optical back-to-back DD-OFDM systems,which implement Double-sideband(DSB)and Single-sideband(SSB)modulation,respectively.The tolerance to IQ imbalance of these two systems is analyzed and compared by using Error Vector Magnitude(EVM)and Symbol Error Rate(SER).It is found that,in the back-to-back case,the DSB system has stronger robustness to IQ imbalance than the SSB System.We further build two optical DD-OFDM systems each with 40-km transmission,which respectively implement DSB and SSB transmission.Similarly,the tolerance to IQ imbalance of these two systems are analyzed and compared in terms of EVM and SER.it is found that,however,in the case of 40-km transmission,the SSB system has stronger robustness to IQ imbalance than the DSB system.As a result,it is concluded that,in the ease of transmission,SSB modulation can enhance the tolerance to IQ imbalance of DD-OFDM systems.