Fig. 1. The diagram of unrepeatered transmission system

Fig. 2. The diagram of simulation structure of unrepeatered transmission system with DRA

Fig. 3. The diagram of simulation structure of unrepeatered transmission system with EDFA only

Fig. 4. Simulation of power distribution of signal in fiber link under two unrepeatered transmission

Fig. 5. The diagram of simulation structure of 4 channel WDM unrepeatered transmission system

Fig. 6. BER of received signal in two simulation with same bit rate

Fig. 7. The experimental setup of real-time unrepeatered transmissio

Fig. 8. The photo of real-time unrepeatered transmission experiment

Fig. 9. BER and the best signal constellations of the single carrier system and 4 channel WDM system in the real-time unrepeatered transmission experiment