Analysis of Confinement Factor in SOA for Optical Communication System Aruna Rani 1 and Sanjeev Dewra 2 1,2 Department of Electronics and Communication Engineering, Shaheed Bhagat Singh State Technical Campus, Ferozepur, Punjab, India E-mail: 1 arunarani70@gmail.com, 2 sanjeev_dewra@yahoo.com Abstract—The 32 channel optical system based on optimized Semiconductor optical amplifier at 10 Gb/s have been investigated in this paper, and the performance of optical system has been analyzed by varying the confinement factor of SOA. The communication over fiber optical link is evaluated upto 245km transmission distance for 0.4 confinement factor of SOA at low input signal power of -40 dBm. It is also evaluated that the signal can be effectively transmitted with acceptable quality of signal and BER upto 157, 201 km for 0.2 & 0.3 confinement factors respectively. Keywords: Semiconductor Optical Amplifier, Dense Wavelength Division Multiplexing System, Quality Factor, Bit Error Rate I. INTRODUCTION A semiconductor optical amplifier (SOA) will be the best aspirant for the optical amplifier considering its compact size, flat-gain, cost-effectiveness, and low- power consumption [1–3]. The use of SOA as multifunctional device allows performing all optical functions based on its nonlinearities [4, 5]. To meet the requirement SOAs are promising because of their compactness and simple current pumping. The gain in a SOA saturates as the optical power level increases [6]. Singh et al. [7] presented the placement of semiconductor optical amplifier for 10Gbps non-return to zero format in dispersion–compensated fiber and single mode fiber link. In this work, different pre, post and symmetrical compensation methods for different locations of the SOA in fiber link have been reported. The impact of increase in signal input power for these three power compensation methods are compared in terms of BER, eye closure penalty and output received power. It was observed that the post power compensation method is better to symmetrical and pre power compensation methods when SOA is used. Woosuk Choi [8] analyzed the performance of 8 × 10 Gb/s transmission over 240 km wavelength division multiplexing system caused by crosstalk in cascaded conventional semiconductor optical amplifiers. Sun et al. [9] investigated an error-free transmission 32 × 2.5 Gb/s DWDM channels over 125 km using cascaded in-line SOAs. Kim et al. [10] successfully transmitted 10Gb/s optical signals over 80km through SSMF using SOAs as booster amplifiers. They have further found the suitable parameters of input signals for SOAs, such as rising/falling time, extinction ratio and chirp parameter to maximize output dynamic range and maximum output power. In this paper, we extended the previous work by increasing the number of channels and transmission distance without any power compensation methods by using DS-Normal fiber only and investigated the performance of SOA for dense wavelength division multiplexed system by varying the confinement factor. This paper is structured as follows. Section I presents introduction. Section II discusses the schematic setup of DWDM system using SOA. In Section III, results of SOA by varying confinement factor are presented and Section IV gives a brief outlook for the conclusion. II. SYSTEM SETUP Figure 1 is a system setup of an optical transmission system using semiconductor optical amplifier. The system consists of 32 channels whose wavelengths ranged from 192.35 THz-193.85 THz with a spacing of 100 GHz. Each transmitter consists of data source, laser source, NRZ rectangular driver, and optical amplitude modulator. Data source generates a pseudorandom binary sequence of data stream. The data is converted into optical signal using continuous wave lorentzian (CW) laser source Data format of the type NRZ rectangular is generated by the modulation driver. The pulses are modulated using Sin2 Mach-Zehnder modulator at 10 Gbps. The combined signals with an optical combiner were modulated simultaneously at 10 Gb/s. The signal was then input to DS-Normal fiber of the reference frequency 192.35 THz, dispersion- 2ps/nm/km and attenuation is 0.2 dB/km. Then the output is fed to semiconductor optical amplifier through an optical splitter. The optimized parameters of SOA used in the simulation are as follows: bias current is 290mA, the length is 400 mm, the width of the active layer is 2 mm, and its thickness is 0.2 mm. The transparency carrier density in the SOA is taken to be 1.5×1018cm 3 , Spontaneous Carrier lifetime is 0.3 ns and the differential gain 3 × 10-16 cm 2 . The input and output coupling losses of SOAs are taken as 3 dB. The optical splitter (S1) is used to measure the optical input power for the transmission link. Optical Power meter and Optical probe with splitter (S2) are used for the measurement of optical signal power and spectrum at different levels.