Optical wireless is the alternative approach to complete the deployment of optical cable networks in case of failure in implementation. In optical wave the attenuation due to atmospheric turbulence conditions causes a performance degradation of a free space optical (FSO) system. Thus, it will lead to the deterioration of the signal power in the optical cable. To overcome these challenges, multi-channel FSO transmitter and erbium doped fiber in optical link was adopted with high transmission power. In this paper, a hybrid FSO/fiber optic (FSO/FO) link is simulated and investigated under different weather conditions. The proposed hybrid link is evaluated in terms of BER and Q-factor. The proposed system shows a closely performance as compared with the conventional FSO for whole investigation range from 200 m to 2000 m. While the communication distance with the hybrid link is increased by 40 km as compared to conventional FSO. The results show good agreement with Kim model, especially at high input power of 160 mW.

In this study, a simulation analysis of 40-Gb/s long-haul (120 km) dense wavelength-division multiplexer system (DWDM) of 32 channels with 50 GHz spacing is conducted for duobinary return-to-zero modulation formats. Pre- and post-dispersion compensation schemes utilizing dispersion compensating fiber (DCF) and fiber Bragg grating (FBG) are analyzed to compare these schemes at high bit rate. Quality factor (Q) and bit error rate (BER) values are used to measure the response of the system as a function of input power for both compensation schemes. The pre-FBG scheme shows a better performance in terms of Q-factor that reached 11.5 at 0 dBm input signal power.

A simple active mode-locked erbium-doped ring fiber laser is proposed. The fiber laser operates in the wavelength range 1525nm to 1565nm. A Gaussian pulse train drives an intensity modulated placed inside the laser cavity. The active mode-locked laser produces a train of pulses with width as low as 30ps at a repetition rate of 1GHz.