**5. Conclusion**

**Figure 30.** Q-factor to transmission length at wavelength 1560 nm.

This is the weaknesses of SOA characteristics.

102 Telecommunication Networks - Trends and Developments

**Figure 29.** BER value over transmission length at wavelength 1560 nm.

geometry length where it can operate either low- or high-energy sources corresponding to wavelength source. Even at 120 km, the highest BER is achieved for 1350 nm (high energy).

Although these data are unknown source of loss factors, improving BER can be detected by choosing strong signal strength, a slow and robust modulation scheme, or line coding scheme or using coding schemes such as redundant forward error correction codes. As well as BER of SOA, Q-factor of SOA goes down as a distance is increased. Q-factor for 1350 nm is even less decayed than the others, although the decay trends are stable beginning from 80 km similar to a constant Q-factor. At 140 km the energy source is not good enough to maintain the oscillation source; the decay goes down near linear for 1350 nm and keeps maintaining to reduce it slowly.

> Although the optical amplifier can maintain the signal along the trajectory of waveguide, several amplifiers still have weaknesses. Both SOA and FRA have advantages and disadvantages. Using the simulation application, both amplifiers are successfully designed and compared by in-line amplifiers. The results described that the transmission distance of the FRA is much farther than the SOA shown by BER and Q-factor. However, this FRA system has higher power consumption when compared to the SOA system.
