【摘要】 设计并实现了单用户、数据速率2.5 Gbit/s的码位重叠快跳频光码分多址(SO-FFH OCDMA)实验系统。采用波长数为7和码长为4的单重合码,在数据速率2.5 Gbit/s时设计和制作了基于光纤布拉格光栅(FBG)的光编码/解码器,并测试了光编码器和光解码器的频谱图。脉冲发生器产生2.5 Gbit/s的非归零(NRZ)脉冲信号,外调制放大自发辐射(ASE)宽带光源后,通过光环行器进入光编码器进行光信号的扩频编码。编码后的光信号经掺铒光纤放大器(EDFA)放大后,输入到光解码器进行扩频解码,并通过2.5 Gbit/s接收模块转换为电信号。从解码信号的波形看,在用户数据速率为2.5 Gbit/s时,该系统能够正确解码用户的数据信息。实验结果表明,相对于传统的快跳频光码分多址系统,码位重叠快跳频光码分多址可大大提高用户的数据速率。更多还原

【Abstract】 Experiment on 2.5 Gbit/s symbol overlapping fast frequency-hopping optical code division multiple access(SO-FFH OCDMA) system with single user is designed and demonstrated.Under(user′s) data rate 2.5 Gbit/s,fiber Bragg grating based optical encoder and decoder are designed and fabricated employing one-coincidence sequence,which the number of wavelengths is seven and code length is four.The spectra of optical encoder and decoder are measured.Pulse generator generates 2.5 Gbit/s non-return zero(NRZ) pulse signal,which is used to externally modulate amplified spontaneous emission(ASE) broadband source,and then optical signal is fed into optical encoder to spread spectrum.At the receiver,an Erbium-doped fiber amplifier(EDFA) is employed to amplify the encoded optical signal,then optical signal is fed into the decoder,and is also converted into electrical signal by(2.5 Gbit/s) receiver module.It can be shown from the waveforms of decoded optical signal and the electronic signal that,(user′s) data can be decoded correctly at 2.5 Gbit/s data rate.Experiment shows that compared with traditional FFH OCDMA,SO-FFH OCDMA has much higher(user′s) data rate.更多还原