**3.1. Information source block**

**3. Design and model of SOA and FRA circuit**

88 Telecommunication Networks - Trends and Developments

in photonic systems [6–9].

rier density at the point of transparency.

*n<sup>2</sup>* = nonlinear refractive index (m<sup>2</sup>

 *– ω<sup>s</sup>*

face (m2

fraction, *Χ1111(ω<sup>p</sup>*

The suitable amplifier is one way to deal with the effects of linear and nonlinear disturbances as well as maximize the working of optical transmission media. Generally the optical amplifier consists of fiber Raman amplifier (FRA), erbium-doped fiber amplifier (EDFA), and semiconductor optical amplifier (SOA). SOA is designed in the form of quantum-dot SOA network as linear network and bulk SOA as nonlinear network [2]. Then, it is known that SOA has a high nonlinear nature, low power consumption, fast operating speed, and can easily be used

where *gm* = material amplifier, *Ag* = coefficient of derivative gain, *N* = carrier density, *N<sup>o</sup>* = car-

where *g<sup>t</sup>* = coefficient of amplifier, *Γ* = optical confinement factor, α = effective loss coefficient.

Then, Bromage introduced the RA used in fiber-optic communication systems [10]. The gain

where *G* = magnitude of gain (dB), *P* = power pump (Watt), *L* = length of optical fiber (m),

Both amplifiers show that the type of SOA more considered the carrier density and the material factor, whereas FRA more considered the frequency characteristics and wave nonlinear conditions. However, both amplifiers are very dependent on the media passed by the signal. In order to investigate the performance of SOA and FRA, bit error rate (BER) and Q-factor are

), *λ* = wavelength signal (m), *g* = Raman gain coefficient, *ρ* = nonlinear polarization

), *γ* = nonlinear phase change (rad), *Aeff* = effective sur-

(1)

(2)

(3)

(4)

(5)

(6)

In SOA type amplifier, the gain can be calculated using the following equation:

where *G* = magnitude of gain (dB), *z* = length of optical fiber (dB).

on this amplifier can be calculated using the equation as follows:

. W−<sup>1</sup>

*)* = Raman's susceptibility.

two parameters used to measure their characteristics.

The information source block consists of two components: pseudorandom bit sequence (PRBS) and *non-return-to-zero pulse generator* (NRZ). PRBS functions to generate bits with specific patterns and speeds. Then the bit that has been generated by PRBS will be encoded using NRZ coding technique. NRZ coding technique has the advantage that is more resistant to noise and is not affected by the voltage level. **Figure 6** shows the planning drawing for the source of pulse information.

**Figure 5.** Model design with amplifier.

**Figure 8.** Transmission media block.

Optical Amplifiers for Next-Generation Telecommunication

http://dx.doi.org/10.5772/intechopen.79941

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**Figure 10.** Optical fiber system scheme with SOA in-line amplifier.

**Figure 11.** Optical fiber system scheme with FRA in-line amplifier.

**Figure 9.** Receiver block.

**Figure 6.** Information source block.

### **3.2. Transmitter block**

The transmitter block (**Figure 7**) consists of two components: the laser and the modulator. The laser acts as a light signal generator on a network system. The type of laser used is a continuous wave (CW) laser. The modulator used is the Mach-Zehnder modulator (MZM) which will modulate the coded information signal with the output signal laser.

#### **3.3. Transmission media block**

The transmission medium (**Figure 8**) on this optical network uses single-mode optical fiber, because it has a wide bandwidth and a considerable range. In order for the transmitted signal to reach a considerable distance, it requires an optical amplifier, SOA and FRA. Type of TRD used is average power model amplifier (APA).

#### **3.4. Receiver block**

The receiver block consists of two components: a detector and a filter. The detector used is avalanche photodiode (APD) as shown in **Figure 9**, because it has a faster response and higher gain. The already converted information signal will be forwarded to the filter. The working principle of this filter passes a certain frequency and dampens other frequencies. The type of filter used is the *low-pass Bessel filter*.

The stages of this procedure begin with a preliminary simulation process that aims to determine the maximum transmission distance of signal propagation on the optical fiber without any gain. In the simulation process, it will iterate on the optical fiber, for 30 iterations, and each iteration is 10 km. Then, the determination of maximum transmission distance is demonstrated by using SOA and FRA. The working procedure of these two optical amplifiers can be seen in **Figures 10** and **11**. The length of fiber optics greatly affects the performance of a communication system. In determining the maximum transmission length, the parameters that

**Figure 7.** Transmitter block.

**Figure 8.** Transmission media block.

**Figure 9.** Receiver block.

**Figure 10.** Optical fiber system scheme with SOA in-line amplifier.

**Figure 11.** Optical fiber system scheme with FRA in-line amplifier.

**Figure 7.** Transmitter block.

**3.2. Transmitter block**

**Figure 6.** Information source block.

90 Telecommunication Networks - Trends and Developments

**3.4. Receiver block**

**3.3. Transmission media block**

used is average power model amplifier (APA).

filter used is the *low-pass Bessel filter*.

The transmitter block (**Figure 7**) consists of two components: the laser and the modulator. The laser acts as a light signal generator on a network system. The type of laser used is a continuous wave (CW) laser. The modulator used is the Mach-Zehnder modulator (MZM) which will

The transmission medium (**Figure 8**) on this optical network uses single-mode optical fiber, because it has a wide bandwidth and a considerable range. In order for the transmitted signal to reach a considerable distance, it requires an optical amplifier, SOA and FRA. Type of TRD

The receiver block consists of two components: a detector and a filter. The detector used is avalanche photodiode (APD) as shown in **Figure 9**, because it has a faster response and higher gain. The already converted information signal will be forwarded to the filter. The working principle of this filter passes a certain frequency and dampens other frequencies. The type of

The stages of this procedure begin with a preliminary simulation process that aims to determine the maximum transmission distance of signal propagation on the optical fiber without any gain. In the simulation process, it will iterate on the optical fiber, for 30 iterations, and each iteration is 10 km. Then, the determination of maximum transmission distance is demonstrated by using SOA and FRA. The working procedure of these two optical amplifiers can be seen in **Figures 10** and **11**. The length of fiber optics greatly affects the performance of a communication system. In determining the maximum transmission length, the parameters that

modulate the coded information signal with the output signal laser.

play an important role are the bit error rate (BER) and Q-factor. According to the rules of the International Telecommunication Union (ITU-T G.691; ITU-T G.692; ITU-T G.693), the BER requirements for optical communication systems must be better than 10−12, meaning that the minimum value of BER system should be smaller than 10−<sup>12</sup>. Q-factor is a quality factor that will determine the quality of a link. In a fiber-optic communication system, the minimum size of a good Q-factor is 6. The power consumption of the amplifier will be measured using the optical power meter contained in the circuit. We will then see the influence of the wavelength on the maximum transmission distance of the system.
