8 × 10-Gb/s transmission system over 1500 km on G.652 fiber dispersion compensated by chirped fiber gratings

The impact of dispersion on system performance in- creases as the operating bandwidth increases and also as the transmission distance and bit rate increase. To overcome the dispersion limit, various dispersion com- pensation techniques have been used. Dispersion com- pensation fiber (DCF) has been used popularly. How- ever, DCF is expensive. Sometimes, erbium-doped fiber amplifier (EDFA) is needed to compensate for the in- sertion loss of the DCF and the costs are high. Besides that, the…     

利用CFBG补偿色散实现2 015 km 8×10 Gb/s光传输

利用啁啾光纤光栅(CFBG)串联的多波长色散补偿器对长距离传输的8个信道信号进行色散补偿,各个信道波长符合ITU-T标准,波长间隔为100 G.系统采用掺Er3+光纤放大器(EDFA)作为功率放大器,在2 015 km的G.652光纤上无前向纠错(FEC)无电中继实现8×10 Gb/s零误码传输.结果表明,利用CFBG构成的色散补偿器各信道补偿一致性好,CFBG不但能通过滤除带外噪声有效减小长距离传输中由放大器产生的自发辐射噪声(ASE)的积累,提高传输信号的信噪比(OSNR),而且其较低的非线性特性有利于抑止信号劣化,从而有效提高长距离波分复用(WDM)的传输性能,扩展无电中继传输距离.     

Multiwavelength All-Optical Clock Recovery of Non-Return-to-Zero Data

A novel scheme of all-optical clock recovery from mutiwavelength non-return-to-zero （NRZ） data stream is proposed and demonstrated. The chirp induced by a chirped fibre Bragg grating and a semiconductor optical amplifier is used to enhance the clock. The clock is recovered after injecting the enhanced signal into the scheme based on the stimulated Brillouin scattering. The experiment is carried out and the dual-wavelength clock is recovered. This novel scheme can realize clock recovery of multiwavelength NRZ signal in the total wavelength range of 3.3nm. This clock recovery technology is transparent to the data bit rate and modulation format, also without pattern dependence.     

10Gbps-RZ光信号在光纤光栅色散补偿的2500km无电中继系统中的传输

全部利用线性啁啾光纤布拉格光栅(CBG)作色散补偿模块和在线通道滤波器,在2500km G.652光纤上实现10Gbps-RZ光信号的超长距离无电中继传输。在2081km处,功率代价~3dBm(RZ码,BER=10-12,PRBS=1023-1);在2560km处,功率代价~5dBm,远优于相同系统平台下NRZ无误码传输时的性能。     

啁啾光纤光栅波长路由光网络的组播功能实现

在基于光路交换的4节点16×10 Gbps双纤单向新型分布式全光自愈环网上,利用啁啾光纤光栅(CFBG)和环行器等无源器件实现了光层组播,避免了光/电/光转换.CFBG在网络中用于实现色散补偿、上下话路和波长路由.通过调节光栅的中心波长,分别完成对控制信息、组播业务信息的分别读取.整个网络不存在关键性节点,每个节点都可以作为组播业务的发起端和接收端.根据控制信息配置传输信道,提高了组播数据流的传输效率.研究结果表明,这种组播方式具有物理实现简单、安全性高、对组播数据速率和格式透明以及数据传输无阻塞等特点.     

光栅不理想特性对不同调制码型的光传输系统的影响

分析了光纤光栅不理想特性的产生机理，对以啁啾光纤光栅为色散补偿器的10Gb/s光传输系统中，啁啾光纤光栅的不理想特性包括群时延纹波、反射纹波及光栅通带带宽对采用归零码(RZ)、非归零码(NRZ)以及载波抑制归零码(CSRZ)三种调制格式传输系统性能的影响进行了详细的数值分析和比较. 同时进行了基于光纤光栅色散补偿的1500km无误码传输实验，通过对啁啾光纤光栅由于不理想特性的差别而导致对实际传输系统不同信道性能影响的比较，进一步验证了仿真分析的正确性. 关键词： 光传输 啁啾光纤光栅 不理想特性 调制码型     

恶化非归零码信号的全光时钟恢复

全光时钟提取结构应对输入信号的恶化程度有一定的容忍度.在一种半导体光放大器(SOA) 啁啾光纤布拉格光栅(CFBG) 受激布里渊散射(SBS)的方式实现非归零(NRZ)码信号的全光时钟提取结构中,半导体光放大器和啁啾光纤布拉格光栅共同作用实现了非归零码信号的时钟分量增强,基于受激布里渊散射的全光时钟提取结构提取出非归零码的光时钟信号.实验通过对不同恶化程度的非归零码信号的时钟提取比较发现,恶化信号的信噪比是影响光时钟提取的关键.输入非归零码信号的信噪比越差,光时钟信号光谱的噪声水平越高,提取出的光时钟信号的幅度越低.当时钟增强非归零码信号的时钟数据抑制比低于-10 dB时,无法实现非归零码信号的时钟提取.     

Zero-Chirp Return-to-Zero Pulses Generation with Two Single-Driver z-Cut Mach-Zehnder Modulators

A novel method is proposed to suppress the frequency chirp of single-driver z-cut Mach Zehnder modulators. Theoretical analysis shows that by multiplying the output pulses of a half clock frequency driving single-driver z-cut modulator with the one delayed odd multiple bit duration, the frequency chirp can be removed entirely, and return-to-zero （RZ） pulses with duty cycles of about 25% and 56% are obtained. An experimental scheme is proposed to validate the proposed method. The pulses can be obtained by using this scheme. experimental results show that perfect 40 GHz zero-chirp RZ     

RZ、CSRZ码在CBG色散补偿系统中的传输

全部利用线性啁啾光纤布拉格光栅（CBG）作色散补偿模块和在线通道滤波顺，在2500km超长距离的G．652光纤上实现10Ghps归零码（RZ）、载波抑制归零码（CSRZ）光信号的无电中继传输，并在2080km和2560km处分别对2种信号的传输性能进行了测试。CSRZ在上述2处的功率代价分别为～1dBm和～3dBm（BER-10^12，PRBS=10^23-1），RZ的功率代价分别为～3dBm和～5dBm，验证了在相同系统平台下CSRZ光信号比RZ光信号有更好的性能.