产生暗归零码光标记信号的新方案

在对预编码、调制和编码过程进行改进的基础上,提出了一种利用一个双臂马赫-曾德尔铌酸锂调制器和一个电信号时延器产生可调占空比和消光比的光暗脉冲归零码二进制信号的新方案。实验证明这种信号能用传统的二进制强度调制-直接检测系统的接收机进行检测。实验得到了在调节电信号时延器时速率为2.5 Gbit/s的光暗脉冲归零码二进制信号的频谱变化规律,以及占空比分别为0.25,0.35,0.60和0.80时光暗脉冲归零码二进制信号的误码率和眼图。此外,利用该方案产生的光暗脉冲归零码二进制信号可以作为标记在光标记交换网络中得到应用。

A Novel Scheme for Generation of Optical Dark Return-to-Zero Label Signals

A novel scheme to generate binary optical dark return-to-zero(RZ) signals with tunable duty cycle and extinction ratio is proposed,through modifying the process of precoding,modulating and coding.The optical dark return-to-zero signals are easily generated only by using a dual-arm Mach-Zehnder LiNbO3 modulator along with an electrical signal time-delay device.It is demonstrated experimentally that the optical dark return-to-zero signals can be directly measured by a conventional binary intensity modulation-direct detection(IM-DD) receiver.When the electrical signal time-delay device at 2.5 Gbit/s is adjusted,the changes of optical spectra,the bit-error rate curves,and the eye diagrams of the optical dark return-to-zero signal for duty of cycles 0.25,0.35,0.60 and 0.80 are obtained experimentally.Moreover,optical dark return-to-zero signals generated by this novel scheme can be used as labels,in optical label switched networks.