级联3个相位调制器产生光8-DPSK的新方法

提出级联3个相位调制器产生光NRZ-g-DPSK,再级联1个单臂马赫-曾德尔(M-Z)调制器产生光RZ-8-DPSK的新方案.比较了背对背系统中60Gb/s的光NRZ-8-DPSK、光差分相移键控非归零码(NRZ-DPSK)和光差分四相相移键控码(NRZ-DQPSK)的信号频谱特性.     

四种级联差分相位调制码的100 Gbit/s传输

在级联相位调制的100 Gbit/s光信号传输系统中,对差分相移键控非归零码(NRZ-DPSK)、差分相移键控归零码(RZ-DPSK)、差分四相相移键控非归零码(NRZ-DQPSK)和差分四相相移键控归零码(RZ-DQPSK)进行了比较研究.当四种信号通过90 km的标准单模光纤(SMF)和16 km的色散补偿光纤(DCF)传输后,在满足相同入纤功率的条件下,NRZ-DQPSK信号具有最高的色散容限;如果仪仪考虑一阶偏振模色散(PMD),RZ-DQPSK信号具有最优的抗偏振模色散特性;当入纤功率在O～10 dBm的范围内凋节时,RZ-DPSK信号具有最好的非线性容忍度;最后比较了四种相位调制码型传输后通过不同带宽的三阶高斯滤波器后的接收性能,得出滤波器带宽值大于125 GHz后,NRZ-DPSK信号的接收性能最佳.     

基于光纤差分相移键控的色散补偿方案的研究

为了研究光差分相移键控(DPSK)调制格式在光纤高速传输系统中的色散补偿, 利用色散补偿光纤(DCF)的色散补偿原理, 对40Gbit/s光纤传输系统进行色散补偿, 分析了40Gbit/s单通道光纤传输系统中3种DPSK调制格式信号的频谱特性; 仿真了3种码型的色散容忍度以及3种调制格式在考虑光纤的非线性下的色散补偿方案。结果表明, 光非归零码差分相移键控(NRZ-DPSK)信号具有最好的色散容忍度, 但其受非线性的影响比较大; 33%归零码差分相移键控(33%RZ-DPSK)信号的色散容忍度差, 但其色散补偿后的效果优于NRZ-DPSK; 而载波抑制归零码差分相移键控信号对色散和非线性效应都有较好的抑制; 3种DPSK调制格式均在对称补偿2方案中色散补偿的效果最佳。此仿真研究对光DPSK信号在光纤中的色散补偿具有参考意义。     

新型改进光双二进制传输的编解码方案

提出了改进型光双二进制信号在高速率（≥10Gbit／s）传输时预编码的一种新方案。通过分析编解码过程，证明该信号传输时不易受码间干扰影响，能用二进制强度调制一直接检测的系统接收信号。仿真产生了该信号的2种码型。结果表明，采用色散补偿技术能使MD-NRZ和MD-RZ信号在长距离传输后克服眼图失真，MD-RZ信号比MD-NRZ信号在传输后有更低的误码率。     

DRZ和MD-RZ码光纤传输性能分析

介绍了光双二进制归零码DRZ和改进的双二进制归零码MD-RZ的产生原理和特点,通过光通信仿真软件产生了这两种信号,并给出了光谱图.重点设计了一个40Gb/s的单信道光纤传输系统,对两种码型进行了模拟,通过对Q值的结果来分析其非线性容限和传输距离,并与CSRZ码的传输性能进行对比.     

基于马赫-曾德尔调制器的先进调制格式的产生

提出了一种基于差分马赫-曾德尔调制器(MZM)产生80 Gbit/s高速率差分相移键控归零码(RZ-DPSK)、差分相移键控载波抑制归零码(CSRZ-DPSK)、差分正交相移键控归零码(RZ-DQPSK)、差分正交相移键控载波抑制归零码(CSRZ-DQPSK)的新方法.在采用两个差分MZM级联产生数据速率为80 Gbit/s的RZ/CSRZ-DPSK光信号的基础上,仅需增加一个双驱动MZM,就可以产生RZ/CSRZ-DQPSK信号,说明提出的方法有一定的扩展性,并简化了高速RZ/CSRZ-DQPSK光信号的产生过程.对产生的80 Gbit/s RZ/CSRZ-DPSK和RZ/CSRZ-DQPSK信号进行的仿真结果表明,CSRZ-DPSK信号比RZ-DPSK信号的频谱结构更加紧凑,差分正交相移键控(DQPSK)光谱形状与差分相移键控(DPSK)相同,只是由于RZ/CSRZ-DQPSK在码元速率下传输数据,得到的光谱在频域被压缩.     

改进型光双二进制码的选择与实现

文章对长距离传输系统中使用的码型(改进型光双二进制归零码MD-RZ和光双二进制非归零码MD-NRZ)进行了比较.仿真结果表明:长距离传输时,采用色散补偿技术,MD-RZ信号相对于MD-NRZ信号有更低的误码率和更高的接收机灵敏度.文章还提出了一种使用保偏光纤环路镜像器(PMFLM)产生MD-RZ信号的方法,并在理论上证明了这种全光方法的可行性.     

40 Gbit/s光纤传输系统中先进调制格式的性能分析

使用Optisystem软件,对DRZ(双二进制归零)、MDRZ(改进的双二进制归零)、CSRZ(载波抑制归零)以及RZ-DPSK(归零差分相移键控)四种调制格式在40Gbit/s单信道系统中进行了仿真分析。通过光谱图和眼图及Q值的结果,分析四种调制格式在长距离传输时的性能。     

40Gb/s光纤传输系统中四种调制格式的性能比较

使用Opt i s ys t em软件,对40Gb/s单信道传输系统中非归零(NRZ)、归零(RZ)、光双二进制(ODB)、改进的光双二进制归零(MD-RZ)四种调制格式进行仿真。长距离传输后,MD-RZ的眼睛睁开度最大,Q值也很高,具有较好的色散容限和非线性容限,适合长距离传输。     

新型APol-CSRZ-FSK调制格式的研究

结合了偏振调制、载波抑制归零码和频移键控的优点,提出了一种交替偏振频移键控载波抑制归零码(APol-CSRZ-FSK)调制技术,它可运用于40 Gbit/s光传输系统.利用APol-CSRZ-FSK调制技术实现了40 Gbit/s的长距离光传输的仿真,结果证明APol-CSRZ-FSK具有良好的传输性能,并且是未来WDM-PON或光标记交换网络的候选码型之一.     

Improved optical coding method for orthogonal ASK/DPSK modulation format

Orthogonal ASK/DPSK labeling, which encodes label information on optical carriers in a modulation format, is regarded as a competing scheme to subcarrier multiplexed optical labeling. However, the inherent cross-talk limits the extinction ratio (ER) of the payload and label sensitivity. In this paper, two optical coding methods-Manchester coding and 8B10B coding-which can remarkably improve the system quality to obtain acceptable ER are discussed. A novel optical packet encoding methodmark-insertion coding-is demonstrated to significantly reduce cross-talk between the amplitude shift keying ASK) payload and the differential phase shift keying (DPSK) label through spectrum shaping. The performance of mark-insertion coding depends on the number of inserted 'marks'. Finally, the transmission over a 40 km single mode fiber (SMF) is compared with optical label swapping for a. 40 Gbit/s ASK payload and 2.5 Gbit/s DPSK label under these coding schemes. The experimental result is consistent with the theoretical analysis.     

FSK Modulation Scheme for High-Speed Optical Transmission

In this paper,we describe the generation,detection,and performance of frequency-shift keying (FSK) for high-speed optical transmission and label switching.A non-return-to-zero (NRZ) FSK signal is generated by using two continuous-wave (CW) lasers,one Mach-Zehnder modulator (MZM),and one Mach-Zehnder delay interferometer (MZDI).An RZ-FSK signal is generated by cascading a dual-arm MZM,which is driven by a sinusoidal voltage at half the bit rate.Demodulation can be achieved on 1 bit rate through one MZDI or an array waveguide grating (AWG) demultiplexer with balanced detection.We perform numerical simulation on two types of frequency modulation schemes using MZM or PM,and we determine the effect of frequency tone spacing (FTS) on the generated FSK signal.In the proposed scheme,a novel frequency modulation format has transmission advantages compared with traditional modulation formats such as RZ and differential phase-shift keying (DPSK),under varying dispersion management.The performance of an RZ-FSK signal in a 4 × 40 Gb/s WDM transmission system is discussed.We experiment on transparent wavelength conversion based on four-wave mixing (FWM) in a semiconductor optical amplifier (SOA) and in a highly nonlinear dispersion shifted fiber (HNDSF) for a 40 Gb/s RZ-FSK signal.The feasibility of all-optical signal processing of a high-speed RZ-FSK signal is confirmed.We also determine the receiver power penalty for the RZ-FSK signal after a 100 km standard single-mode fiber (SMF) transmission link with matching dispersion compensating fiber (DCF),under the post-compensation management scheme.Because the frequency modulation format is orthogonal to intensity modulation and vector modulation (polarization shift keying),it can be used in the context of the combined modulation format to decrease the data rate or enhance the symbol rate.It can also be used in orthogonal label-switching as the modulation format for the payload or the label.As an example,we propose a simple orthogonal optical label switching technique based on 40 Gb/s FSK payload and 2.5 Gb/s intensity modulated (IM) label.     

ASK／FSK光标记交换系统中的OBPF谱均衡法

基于幅移键控／频移键控（ASK／FSK）正交调制光标记交换（0LS）系统工作原理,提出了一种利用光带通滤波器（OBPF）对FSK标记进行谱均衡的方法,从而有效改善ASK净荷接收灵敏度。利用仿真,对40Gb／sASK／FSK正交调制OLS系统,在使用3种不同类型OBPF进行谱均衡时的传输性能进行了验证与比较分析。结果表明...     

Investigation of Dispersion Compensation in 2.5 Gbit/s OOK Label and 40 Gbit/s RZ-DPSK Payload Optical Label Switching System Based on Optical Carrier Suppression and Separation

Three dispersion compensation schemes of an optical label switching transmission system were investigated, which employs 40 Ghit/s return zero differential phase-shift keying(RZ-DPSK) payload labeled with 2.5 Gbit/s on-off keying(OOK) signal based on the optical carrier suppression and separation(OCSS) technique. In the system, proposed are the receiver sensitivity of payload and label, achieving -32.4 dBm and -38. 5 dBm, respectively. Using the optimal dispersion compensation scheme, after transmitted over 160 km and 320 km SMF respectively, the label can be recovered without power penalty, while the payload can be recovered with less than 2 dB and 5 dB penalty, respectively.     

Investigation on the combined orthogonal FSK/ASK labeled signal based on cross gain modulation in a SOA

An optical frequency shift keying(FSK) transmitter performed by the cross gain modulation(XGM) in a semiconductor optical amplifier(SOA) is used in an optical label switching(OLS) system with 622 Mbit/s FSK label and 10 Gbit/s amplitude shift keying(ASK) payload.The key parameters in this system are optimized to achieve the best performance of FSK/ASK signal,including the input power of LD,the extinction ratio(ER) of the control light and that of the ASK payload.Besides,the transmission performance of ASK p...     

一种基于D8PSK／ASK正交调制的新型光标记方案研究

深入研究了差分八相移键控（I）8PSK）j幅移键控（AsK）正交调制格式的机理,提出了一种基于D8PsKjASK正交调制的新型光标记方案,利用D8PSK作为载荷的调制方式,ASK作为标记的调制方式,仿真实现了载荷120Gb／s、标记10Gb／s的传输速率。分析了信号的消光比（ER）对误码率（BER）的影响,仿真结果表明...     

A novel orthogonal modulation format of D8PSK/ASK with differential bi-phase encoding and its application in a label switching optical network

The principle of a novel orthogonal modulation format of differential 8-level phase-shift keying amplitude-shift keying (D8PSK/ASK) with differential bi-phase encoding (DBC) is introduced. Based on it, an optical labeling scheme, in which the payload is 100 Gbit/s D8PSK signal and the label is 10 Gbit/s DBC-ASK signal, is proposed and simulated. The results are compared with other current schemes, and the effects of transmission range, modulation extinction ratio (ER) and received power on system performance are analyzed, respectively. The results show that the spectrum efficiency and bit error rate (BER) are improved greatly, and when the modulation ER is increased to 11 dB, the balanced performance between the payload and label is achieved.     

Transmission performance of implicit optical label switching system with coherently detected spectral amplitude code labels

A new optical label switching system with coherently detected implicit spectral amplitude code (SAC) labels is proposed in this paper. The implicit SAC labels are recognized using a frequency-swept local light source oscillator. An explicit SAC-label switching system with 40 Gbit/s intensity modulation (IM) payloads and 156 Mbit/s label and an implicit SAC-label switching system with 2.5 Gbit/s IM payloads and 156 Mbit/s label are both considered. Label and payload bit error rate (BER) performance is assessed and compared by simulations. The results reveal that after 80 km transmission and at the BER of 10-9, the received optical power (ROP) values of label and payload are -8.3 dBm and -23.5 dBm in implicit SAC-label switching system, respectively, while those are -18.2 dBm and -18.6 dBm in explicit SAC-label switching system, respectively. As a result, the payloads of 40 Gbit/s and 2.5 Gbit/s in explicit/implicit SAC-label switching system have little influence on the received payload quality at the BER of 10-9 after 80 km transmission. Finally, a payload of 40 Gbit/s can obtain 12.5 dB optical signal-to-noise ratio (OSNR) after 80 km transmission.     

STOLAS: switching technologies for optically labeled signals

GMPLS-based labeled optical burst switching (LOBS) networks are being considered as the next-generation optical Internet. GMPLS includes wavelength switching next to label and fiber (space) switching. We present a new concept of optically labeling bursts of packets suitable for LOBS networks supported by GMPLS. It is based on angle modulation, which enables control information to modulate the phase or frequency of the optical carrier, while payload data are transmitted via intensity modulation (IM). In particular, the optical label is orthogonally modulated, with respect to the payload, using either frequency shift keying or differential phase shift keying. We present a performance analysis of the modulation schemes by means of simulations where the influence of the payload IM extinction ratio and laser linewidth are investigated. In addition, the transmission performance of an IM/FSK combined modulated signal is experimentally validated at 10 Gb/s, demonstrating at the same time an FSK label swapping operation. Finally, a suitable optical label-controlled switch design is proposed that takes advantage of these novel labeling techniques, and efficiently combines widely tunable, fast switching lasers and SOA-MZI wavelength converters with an arrayed waveguide grating router.