**4.1. Optical circuits without amplifier BER and Q-factor analysis**

The length of the optical fiber used can affect the performance of a fiber-optic communication system. In determining the maximum transmission length, one of the parameters that play an important role is the amount of bit error rate (BER). The BER requirement for the optical communication system should be less than 10−<sup>12</sup>. The first stage is a simulation process without using an optical amplifier to determine the maximum transmission length with laser wavelength variation. BER is shown in **Figure 19**.

Since the data obtained is in a very small order, then the data change in the form of logarithmic functions. The BER value for an optical source with a wavelength of 1350 nm is 2.12 × 10−<sup>12</sup>

**Figure 16.** (a) 1350 nm, 85 km. (b) 1560 nm, 85 km.

**Figure 17.** (a) SOA (BER and Q-factor) 1350 nm, 80 km. (b) SOA (BER, Q-factor) 1560 nm, 160 km.

**Figure 18** is somewhat different than SOA. FRA has a more effective BER and Q-factor. At a distance of less than 90 km, the very sharp eye pattern at 1350 nm wavelength is almost equal to the 1560 nm wavelength. The value of FRA at a distance of 170 km is still more effective than on SOA values both at 1350 nm and at 1560 nm. However at 1560 nm, BER is more sharp as Q-factor as well. BER and Q-factor at 1560 are higher so that the amplifier function is weak

The length of the optical fiber used can affect the performance of a fiber-optic communication system. In determining the maximum transmission length, one of the parameters that play an important role is the amount of bit error rate (BER). The BER requirement for the optical communication system should be less than 10−<sup>12</sup>. The first stage is a simulation process without using an optical amplifier to determine the maximum transmission length with laser

Since the data obtained is in a very small order, then the data change in the form of logarithmic functions. The BER value for an optical source with a wavelength of 1350 nm is 2.12 × 10−<sup>12</sup>

**4.1. Optical circuits without amplifier BER and Q-factor analysis**

wavelength variation. BER is shown in **Figure 19**.

**Figure 16.** (a) 1350 nm, 85 km. (b) 1560 nm, 85 km.

especially at great distances.

**Figure 15.** Q-factor of FRA profile for various energy.

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or −116.74 dB at a distance of 95 km and 3.51 × 10−<sup>9</sup> or −84.55 dB at a distance of 100 km. The BER value for an optical source with a wavelength of 1470 nm is 1.64 × 10−13 or −127.85 dB at a distance of 85 km and 1.66 × 10−<sup>9</sup> or −87.80 dB at a distance of 90 km, whereas the BER value for an optical source with a wavelength of 1560 nm is 1.26 × 10−12 or −119 dB at a distance of 80 km and 3.56 × 10−<sup>9</sup> or −84.49 dB at a distance of 85 km. So it can be concluded from Figure 4.1 that the maximum transmission distance of the fiber-optic communication system without the amplifier is 95 km for the 1350 nm wavelength, 85 km for the 1470 nm wavelength, and 80 km for the 1560 nm wavelength.

In addition to the BER value, Q-factor is one of the parameters used as a reference in determining the quality of the optical circuit. Under the rules of ITU (International Telecommunication Union) in ITU-T G.691; ITU-T G.692; ITU-T G.693, it is agreed that the minimum Q-factor value that must be possessed by an optical communication system is 6. This shows that a circuit can be categorized well if the circuit has a Q-factor above 6. In contrast, the circuit cannot be used if it has a number below that value.

Based on the simulation that has been executed, it obtains that the value of Q-factor at the source wavelength of 1350 nm is 6.59 at a distance of 95 km and 5.79 at a distance of 100 km. At the source wavelength of 1470 nm, the obtained value is 7.28 at a distance of 85 km and 5.91 at a distance of 90 km, while at the wavelength of 1560 nm, the found value is 6.32 at a

**Figure 18.** (a) Raman (BER and Q-factor) 1350 nm, 90 km. (b) Raman (BER and Q-factor) 1350 nm, 170 km.

**Figure 19.** BER value to transmission length.

distance of 80 km and 5.79 at a distance of 85 km. So **Figure 20** corresponds to the BER data obtained where the maximum transmission distance at the source wavelength of 1350 nm is 95 km, 85 km at 1470 nm wavelength, and 80 km at 1560 nm wavelength.

The BER value for an optical source with a wavelength of 1350 nm is 3.25 × 10−12 or −114.88 dB at

with a 1470 nm wavelength is 7.24 × 10−12 or −111.40 dB at a distance of 180 km and 5.63 × 10−<sup>8</sup> or −72.49 dB at a distance of 190 km. The BER value for the optical source with a wavelength

a distance of 170 km. So it can be concluded from the graph that the maximum transmission distance of the fiber-optic communication amplifier SOA system is 190 km for the wavelength of 1350 nm, 180 km for the 1470 nm wavelength, and 160 km for the 1560 nm wavelength.

The Q-factor value (**Figure 22**) at the source wavelength of 1350 nm is 6.87 at a distance of 190 km and 5.86 at a distance of 200 km. At the source wavelength of 1470 nm, the obtained

of 1560 nm is 1.85 × 10−12 or −117.33 dB at a distance of 160 km and 9.51 × 10−<sup>9</sup>

or −86.36 dB at a distance of 200 km. The BER value for an optical source

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or −80.2 dB at

190 km and 2.31 × 10−<sup>9</sup>

**Figure 21.** BER, transmitting on SOA circuit.

**Figure 22.** Q-factor of transmission length in SOA circuit.

#### **4.2. SOA amplifier circuit BER and Q-factor**

SOA is a type of amplifier that uses semiconductors to gain medium gain. SOA has a structure similar to the Fabry-Pérot laser diode, but it has an anti-reflection element on its surface. Unlike other amplifiers, SOA is electronically pumped directly through the current and does not require a separate laser pump. The working principle of SOA is similar to the laser, where in the active part of the semiconductor, the injection current will excite the electrons from the valence band to the conduction band. If there is light as an input signal, then the electron set will be stimulated to return to the valence band by emitting energy to gain reinforcement. Based on the simulation, SOA is depicted in **Figures 21** and **22**.

**Figure 20.** Q-factor on transmission length without amplifier of optical circuit.

**Figure 21.** BER, transmitting on SOA circuit.

**Figure 19.** BER value to transmission length.

96 Telecommunication Networks - Trends and Developments

**4.2. SOA amplifier circuit BER and Q-factor**

distance of 80 km and 5.79 at a distance of 85 km. So **Figure 20** corresponds to the BER data obtained where the maximum transmission distance at the source wavelength of 1350 nm is

SOA is a type of amplifier that uses semiconductors to gain medium gain. SOA has a structure similar to the Fabry-Pérot laser diode, but it has an anti-reflection element on its surface. Unlike other amplifiers, SOA is electronically pumped directly through the current and does not require a separate laser pump. The working principle of SOA is similar to the laser, where in the active part of the semiconductor, the injection current will excite the electrons from the valence band to the conduction band. If there is light as an input signal, then the electron set will be stimulated to return to the valence band by emitting energy to gain reinforcement.

95 km, 85 km at 1470 nm wavelength, and 80 km at 1560 nm wavelength.

**Figure 20.** Q-factor on transmission length without amplifier of optical circuit.

Based on the simulation, SOA is depicted in **Figures 21** and **22**.

The BER value for an optical source with a wavelength of 1350 nm is 3.25 × 10−12 or −114.88 dB at 190 km and 2.31 × 10−<sup>9</sup> or −86.36 dB at a distance of 200 km. The BER value for an optical source with a 1470 nm wavelength is 7.24 × 10−12 or −111.40 dB at a distance of 180 km and 5.63 × 10−<sup>8</sup> or −72.49 dB at a distance of 190 km. The BER value for the optical source with a wavelength of 1560 nm is 1.85 × 10−12 or −117.33 dB at a distance of 160 km and 9.51 × 10−<sup>9</sup> or −80.2 dB at a distance of 170 km. So it can be concluded from the graph that the maximum transmission distance of the fiber-optic communication amplifier SOA system is 190 km for the wavelength of 1350 nm, 180 km for the 1470 nm wavelength, and 160 km for the 1560 nm wavelength.

The Q-factor value (**Figure 22**) at the source wavelength of 1350 nm is 6.87 at a distance of 190 km and 5.86 at a distance of 200 km. At the source wavelength of 1470 nm, the obtained

**Figure 22.** Q-factor of transmission length in SOA 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 at a 1560 nm wavelength.
