Applications Of Advanced Modulation Formats In Optical Label Switching

With the rapid development of Internet and the growth of data-centric services, higher requirements of bandwidth and transmission rate are put on the optical fiber transmission network. Current network can achieve high bit rate transmission through optical fibers; however, a large number of optical/electrical interfaces greatly limit the switching rate which mismatches the large transmission rate. The low-speed electronic data processing greatly restricts the further upgrade of transmission rate and the utilization of network resources. As there is still a long way to realize all-optical switching, the combination of optics and electronics technology becomes a best choice. Considering the proceeding of current electronic devices development, All-Optical Label Switching (AOLS) is proposed, which is essentially based on optical-electrical hybrid technology. The main principle of All-Optical label switching is as follows:the high-speed data services transmit and switch in the optical domain, realizing all-optical switching; while the low-speed label which carries routing and control information is converted into electrical signal for processing at each switching node.Based on that background, this paper studies the applications of advanced modulation formats in optical label switching. The content consists of two main parts:1. A novel high-speed orthogonal system based on DP-QPSK/ASK Combined Modulation Format is proposed and studied. The scheme employs 111 Gbit/s DP-QPSK format as payload and 27.75Gbit/s ASK format as label after analyzing the orthogonal optical label switching technology. First, the orthogonal system is designed by several modules, and each of them is simulated. After that, the joint modulation system model is established. The impacts of key parameters such as optical filtering and laser linewidth on the system performance are also analyzed. Simulation result shows that DP-QPSK/ASK modulation format can be applied for future 100Gbit/s system by using established components of 10/40 Gbit/s systems.2. A novel way to implement Optical Carrier Suppression and Separation (OCSS) is proposed and the impacts of parameters of Mach-Zehnder(M-Z) are analyzed. Then a novel OCSS Labeling system is proposed, using 10 Gbit/s or 40 Gbit/s Duobinary advanced modulation format as payload and 2.5Gbit/s ASK or Duobinary format as label. The system is designed in modularized type. The OCSS Label switching system is built up with Duobinary payload and various modulation formats of the label. The payloads and the labels are also set to different bit rates. The impacts of key parameters such as demultiplexer bandwidth and FBG filter bandwidth on system performance from four different aspects are analyzed. The proposed OCSS Labeling system exhibits the advantages of compact architecture, low cost, easy control, and low crosstalk between the payload and label, which makes it much more applicable in practical networks.