Performance Analysis and Link Design of Long Haul Coherent Optical OFDM Systems Master’s Thesis in Electrical Engineering

iii Preface I would like to thank my supervisor Dr. Jörgen Carlsson, Professor Hakan Pettersson and Dr. Lars Landin for their precious time and help. I am extremely glad that they made it possible for me to have such a high level education. I would like to thank Emil Nilsson for his continuous help even he was so busy. My thanks to Eva Strid Andersson for her support whenever I need. iv Abstract Orthogonal Frequency Division Multiplexing (OFDM) is a suitable solution due to its many advantages known in wireless communications. On the other hand, optical communications is also used as a backbone to transmit and receive large data rates with economical and good performance. Recently, fiber optical communication and OFDM method are combined to obtain both advantages in a communication link. Coherent optical OFDM (CO-OFDM) has recently been proposed against the chromatic dispersion effect in electrical domain. According to the ITU-T standards there are 111 channels (C and L bands) can be used (191.4 to 185.9 THz) at 50 GHz spacing. Thanks to Wavelength Division Multiplexing, even we use only one RF carrier, we can reach 1.7 Tb/s (111*16 Gb/s) using only one optical cable and utilizing C and L bands. In this research, CO-OFDM technique is modeled and simulated by designing a Monte Carlo simulation. In this simulation, dispersion, data rate, SNR-BER and BER-Distance variations are calculated and results are given in graphical forms. These graphics show the performance of the CO-OFDM system in 5, 8 and 16 Gb/s at different distances for one RF carrier and one optical carrier. It is also shown that how to get 64 Gb/s data rate using the same structure with one optical carrier. v Abbreviations a : Fiber core diameter Ac(t) : OFDM carrier amplitude arg : Symbol phase angle APD : Avalanche Photodiode B : Magnetic field vector BW : Bandwidth BWOFDM : Bandwidth of an OFDM symbol BER : Bit Error Rate BPSK : Binary Phase Shift Keying c : Light velocity in vacuum ik x : The component of k th subcarrier of i th symbol at transmitter output ik y : The component of k th subcarrier of i th symbol at receiver input fs ik x : The component of k th subcarrier of i th symbol after laser phase noise compensation at receiver  i  : Estimated constant laser phase drift θ0 : Constant …