**4.3. RFA circuit: BER and Q-factor**

RA works based on the principle of scattering Raman (Raman scattering). This amplifier does not use a special medium/fiber for strengthening but uses only its transmission media. The characteristics of RA include:


When a monochromatic light engulfs or crashes into a particle, there will be a certain interaction between the light and the particles it has hit. Light will be reflected, absorbed/refracted, or scattered. If scattering causes wavelength changes, then this phenomenon is called Raman scattering producing higher power.

The BER value for an optical source with a wavelength of 1350 nm is 6.98 × 10−12 or

BER value for an optical source with a 1470 nm wavelength is 4.01 × 10−12 or −113.97 dB at

an optical source with a wavelength of 1560 nm is 2.94 × 10−12 or −115.32 dB at a distance

that the maximum transmission distance of the fiber-optic communication amplifier FRA system is 200 km for 1350 nm wavelength, 180 km for 1470 nm wavelength, and 170 km

The Q-factor value in **Figure 24** at the source wavelength of 1350 nm is 6.06 at a distance of 200 km and 5.11 at a distance of 210 km. At the source wavelength of 1470 nm, the obtained value is 6.14 at a distance of 180 km and 5.30 at a distance of 190 km, while at the wavelength of 1560 nm, the found value is 6.42 at a distance of 170 km and 4.82 at a distance of 180 km. So this result corresponds to the BER data obtained where the maximum transmission distance at the source wavelength of 1350 nm is 200 km, 180 km at the 1470 nm wavelength, and

Based on **Figures 25** and **26**, it can be seen at the stance the SOA reinforcement system is 180 km. But the BER value in the SOA amplifier circuit is larger, and the Q-factor is smaller than the FRA amplifier circuit. While in the circuit without the amplifier, the maximum trans-

Based on **Figures 27** and **28**, at the 1350 nm source wavelength, the FRA amplifier optical circuit has a longer transmission distance than the SOA system, where the maximum distance on the FRA amplifier circuit is 200 km while the maximum distance on the SOA circuit is only

**4.4. Comparison between BER and Q-factor without amplifier SOA and FRA**

or −67.90 dB at a distance of 210 km. The

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or −72.42 dB at a distance of 190 km. The BER value for

or −61.48 dB at a distance of 180 km. So it can be concluded

−111.56 dB at a distance of 200 km and 1.62 × 10−<sup>7</sup>

**Figure 24.** Q-factor of transmission length on the FRA circuit.

a distance of 180 km and 5.73 × 10−<sup>8</sup>

170 km at the 1560 nm wavelength.

mission distance is only worth 90 km.

of 170 km and 7.11 × 10−<sup>7</sup>

for 1560 nm wavelength.

The RA is an additional component of the development of the EDFA optical amplifier. Raman launches high-power laser into the optical waveguide in the opposite direction of the source signal. The photon injection amplifies the optical signal where it is needed almost at all over long distances. Reinforcement Raman can make signal boosters more than 10 dB, where skipping for longer distances. Also it allows optical network to achieve transmission speed up to 40 Gbits/s.

The nonlinear effect will appear in the fiber transmission which is the result of signal amplification if the optical signal is pumped by the wavelength and power is released into the fiber. Based on the simulation, FRA is depicted in **Figures 23** and **24**.

**Figure 23.** Graph of BER value to transmission length on FRA circuit.

**Figure 24.** Q-factor of transmission length on the FRA circuit.

**Figure 23.** Graph of BER value to transmission length on FRA circuit.

value is 6.58 at a distance of 180 km and 5.30 at a distance of 190 km, while at the wavelength of 1560 nm, the found value is 6.61 at a distance of 160 km and 5.62 at a distance of 170 km. So this result corresponds to the BER data obtained where the maximum transmission distance at the source wavelength of 1350 nm is 190 km, 180 km at 1470 nm wavelength, and 160 km

RA works based on the principle of scattering Raman (Raman scattering). This amplifier does not use a special medium/fiber for strengthening but uses only its transmission media. The

• Effectively SRS deprives the energy of shorter wavelengths and gives it to longer wavelengths. When a monochromatic light engulfs or crashes into a particle, there will be a certain interaction between the light and the particles it has hit. Light will be reflected, absorbed/refracted, or scattered. If scattering causes wavelength changes, then this phenomenon is called Raman

The RA is an additional component of the development of the EDFA optical amplifier. Raman launches high-power laser into the optical waveguide in the opposite direction of the source signal. The photon injection amplifies the optical signal where it is needed almost at all over long distances. Reinforcement Raman can make signal boosters more than 10 dB, where skipping for longer distances. Also it allows optical network to achieve transmission speed up to 40 Gbits/s. The nonlinear effect will appear in the fiber transmission which is the result of signal amplification if the optical signal is pumped by the wavelength and power is released into the fiber.

• The strengthening mechanism uses stimulated Raman scattering (SRS).

Based on the simulation, FRA is depicted in **Figures 23** and **24**.

at a 1560 nm wavelength.

**4.3. RFA circuit: BER and Q-factor**

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scattering producing higher power.

characteristics of RA include:

The BER value for an optical source with a wavelength of 1350 nm is 6.98 × 10−12 or −111.56 dB at a distance of 200 km and 1.62 × 10−<sup>7</sup> or −67.90 dB at a distance of 210 km. The BER value for an optical source with a 1470 nm wavelength is 4.01 × 10−12 or −113.97 dB at a distance of 180 km and 5.73 × 10−<sup>8</sup> or −72.42 dB at a distance of 190 km. The BER value for an optical source with a wavelength of 1560 nm is 2.94 × 10−12 or −115.32 dB at a distance of 170 km and 7.11 × 10−<sup>7</sup> or −61.48 dB at a distance of 180 km. So it can be concluded that the maximum transmission distance of the fiber-optic communication amplifier FRA system is 200 km for 1350 nm wavelength, 180 km for 1470 nm wavelength, and 170 km for 1560 nm wavelength.

The Q-factor value in **Figure 24** at the source wavelength of 1350 nm is 6.06 at a distance of 200 km and 5.11 at a distance of 210 km. At the source wavelength of 1470 nm, the obtained value is 6.14 at a distance of 180 km and 5.30 at a distance of 190 km, while at the wavelength of 1560 nm, the found value is 6.42 at a distance of 170 km and 4.82 at a distance of 180 km. So this result corresponds to the BER data obtained where the maximum transmission distance at the source wavelength of 1350 nm is 200 km, 180 km at the 1470 nm wavelength, and 170 km at the 1560 nm wavelength.

### **4.4. Comparison between BER and Q-factor without amplifier SOA and FRA**

Based on **Figures 25** and **26**, it can be seen at the stance the SOA reinforcement system is 180 km. But the BER value in the SOA amplifier circuit is larger, and the Q-factor is smaller than the FRA amplifier circuit. While in the circuit without the amplifier, the maximum transmission distance is only worth 90 km.

Based on **Figures 27** and **28**, at the 1350 nm source wavelength, the FRA amplifier optical circuit has a longer transmission distance than the SOA system, where the maximum distance on the FRA amplifier circuit is 200 km while the maximum distance on the SOA circuit is only

**Figure 25.** BER value over transmission length at wavelength of 1470 nm.

190 km. While in the circuit without the amplifier, the maximum transmission distance is only worth 90 km. This proves the role of the optical amplifier used so that the signal can propagate further when compared to the circuit without amplifier.

**4.5. SOA and FRA: BER and Q-factor**

**Figure 27.** BER to transmission over wavelength at wavelength 1350 nm.

**Figure 28.** Q-factor over transmission length for wavelength 1350 nm.

The result of SOA of BER can be analyzed using computer simulations. When a simple transmission model and data source mode are considered, the BER can also be calculated analytically. In the absence of device for BER analysis, OTDR has been used for detecting signal losses in optical fiber and the OptiSystem software for analyzing the BER. The circuit diagram is used to do this analysis. BER is found in SOA where 1350 nm wavelength with 1 mW input power is better than the others since it has higher energy than 1470 and 1560 nm, so that BER oscillation depends on energy. However, after about 150 km, BER value increases. It is not surprising when the distance is long then the error will come; this is due to attenuation of

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Based on **Figures 29** and **30** it can be seen at the largest source wavelength of 1560 nm, the TRA amplifier optical circuit has a longer transmission distance than the SOA system, where the maximum distance on the FRA amplifier circuit is 170 km while the maximum distance in the SOA circuit is only 160 km. While in the circuit without the amplifier, the maximum transmission distance is only worth 80 km.

**Figure 26.** Q-factor to transmission distance at wavelength 1470 nm.

**Figure 27.** BER to transmission over wavelength at wavelength 1350 nm.

#### **4.5. SOA and FRA: BER and Q-factor**

The result of SOA of BER can be analyzed using computer simulations. When a simple transmission model and data source mode are considered, the BER can also be calculated analytically. In the absence of device for BER analysis, OTDR has been used for detecting signal losses in optical fiber and the OptiSystem software for analyzing the BER. The circuit diagram is used to do this analysis. BER is found in SOA where 1350 nm wavelength with 1 mW input power is better than the others since it has higher energy than 1470 and 1560 nm, so that BER oscillation depends on energy. However, after about 150 km, BER value increases. It is not surprising when the distance is long then the error will come; this is due to attenuation of

**Figure 28.** Q-factor over transmission length for wavelength 1350 nm.

**Figure 26.** Q-factor to transmission distance at wavelength 1470 nm.

further when compared to the circuit without amplifier.

**Figure 25.** BER value over transmission length at wavelength of 1470 nm.

transmission distance is only worth 80 km.

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190 km. While in the circuit without the amplifier, the maximum transmission distance is only worth 90 km. This proves the role of the optical amplifier used so that the signal can propagate

Based on **Figures 29** and **30** it can be seen at the largest source wavelength of 1560 nm, the TRA amplifier optical circuit has a longer transmission distance than the SOA system, where the maximum distance on the FRA amplifier circuit is 170 km while the maximum distance in the SOA circuit is only 160 km. While in the circuit without the amplifier, the maximum

**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). This is the weaknesses of SOA characteristics.

Unlike SOA, FRA has good performance for both BER and Q-factor. BER is less fluctuated and more stable for higher energy of *E = hf*, where *f* is frequency source, *h* is Planck constant, and *E* is energy. From 60 to 140 km, BER is nearly constant for various wavelength sources; hence, this BER is better than BER of SOA. Q-factor is faster for a stable condition at higher energy at 80 km and continues after 160 km. This performance shows that at wavelength of 1350 nm, the

**Amplifier Power input (dBm)**

190 FRA 0 −61.302 61.302

180 FRA 0 −59.499 59.499

160 FRA 0 −55.740 55.740

1350 100 FRA 0 −43.533 43.533

1470 100 FRA 0 −43.565 43.565

1560 100 FRA 0 −43.752 43.752

**Power output (dBm)**

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SOA 0 −41.737 41.737

SOA 0 −59.592 59.592

SOA 0 −41.622 41,622

SOA 0 −57.880 57.880

SOA 0 −41.808 41.808

SOA 0 −53.794 53.794

**Power consumption** 

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**(dBm)**

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The measured power consumption is the power consumption in the FRA circuit and the SOA circuit. The input power used in both circuit types is 1 mW or 0 dBm. This input power comes from the laser, and the output power is measured on the detector device. The power measurement uses an optical power meter and an electrical power meter at the output that can calculate the signal power passing through which the device is placed. Power consumption is obtained by calculating the input power difference with output power. From **Table 1** it can be seen at wavelengths of 1350, 1470, and 1560 nm for in-line amplifier implementation, the power consumption of the SOA is smaller than that of the FRA circuit. The SOA has slightly more energy efficient when compared to the FRA requiring a pumping laser so that the lost power is greater.

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

dispersion is more than the wavelength of 1560 nm, but Q-factor oscillation is low.

**4.6. Power consumption**

**Table 1.** Power consumption to FRA than SOA.

**Wavelength source** 

**Transmission length (km)**

**(nm)**

**5. Conclusion**

consumption when compared to the SOA system.

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.

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


**Table 1.** Power consumption to FRA than SOA.

Unlike SOA, FRA has good performance for both BER and Q-factor. BER is less fluctuated and more stable for higher energy of *E = hf*, where *f* is frequency source, *h* is Planck constant, and *E* is energy. From 60 to 140 km, BER is nearly constant for various wavelength sources; hence, this BER is better than BER of SOA. Q-factor is faster for a stable condition at higher energy at 80 km and continues after 160 km. This performance shows that at wavelength of 1350 nm, the dispersion is more than the wavelength of 1560 nm, but Q-factor oscillation is low.

#### **4.6. Power consumption**

The measured power consumption is the power consumption in the FRA circuit and the SOA circuit. The input power used in both circuit types is 1 mW or 0 dBm. This input power comes from the laser, and the output power is measured on the detector device. The power measurement uses an optical power meter and an electrical power meter at the output that can calculate the signal power passing through which the device is placed. Power consumption is obtained by calculating the input power difference with output power. From **Table 1** it can be seen at wavelengths of 1350, 1470, and 1560 nm for in-line amplifier implementation, the power consumption of the SOA is smaller than that of the FRA circuit. The SOA has slightly more energy efficient when compared to the FRA requiring a pumping laser so that the lost power is greater.
