超结构光纤光栅的正交波分复用系统实现方案及接收机串扰分析

解释了超结构光纤光栅(SSFBG)作为脉冲成型滤波器的特性,说明SSFBG能够产生规则的时域矩形光脉冲,在频域上功率谱密度表现为sinc函数的形式.当光波道的频率间隔为码元速率的整数倍时,相邻波长的功率谱零点位于信号波长的中心频率处,频谱正交交叠.研究了一种基于SSFBG的正交波分复用(OWDM)系统,发送端用SSFBG进行脉冲整形,接收端采用窄带滤波器.给出基于理想窄带滤波器和高斯窄带滤波器两种接收机的串扰噪声模型,并得出了仿真结果.结果显示,两种窄带滤波器均可抑制严重的信道串扰,当接收机窄带滤波器通带足够窄时,接收机串扰比信道串扰降低约10 dB;理想窄带滤波器优于高斯窄带滤波器2～5 dB.

Implementation of Superstructure Fiber Bragg Gratings-Orthogonal Wavelength Division Multiplexing and Analysis of Receiver Crosstalk

The characteristics of superstructure fiber Bragg gratings (SSFBG) as pulse shaping filters were illustrated. It was interpreted that SSFBG can produce regular rectangle optical pulses in time domain whose optical power spectral density in frequency domain is sinc function. When channel separation was integral times of optical code rate, the neighbor channel presents zero point at the center frequency of signal channel, and the frequency spectrum were orthogonally overlapped. An orthogonal wavelength division multiplexing(OWDM) system based on SSFBG was presented. The system consists of SSFBG in transmitter works as pulse shaper and a narrow band filer in receiver. Mathematic models and simulation results are presented for the ideal narrow pass filter (NPF) and Gaussian filter receiver crosstalk. The simulation results show that both the ideal NPF and Gaussian filter can minimize the inter channel crosstalk. The crosstalk of receiver is weaker than channel crosstalk by about 10 dB when the filter in receiver is narrow enough. The crosstalk of ideal NPF receiver is weaker than Gaussian filter receiver by about 2～5 dB.