Photonic Generation of Millimeter Waves Using Tandem Mach-Zehnder Modulators for a W-Band OCDMA-over-WDM Radio-over-Fiber System
The goal of my research has been to investigate methods to effectively increase the capacity of fiber optic networks to be compliant with the extra-large capacity requirements of the next generation of mobile communication systems (5G). The first method to increase the capacity is to elevate the working frequency to the millimeter wave range. Radio-over-Fiber systems are well established yet very promising in effectively expanding the capacity. The second investigated method is to incorporate wavelength division multiplexing into the Radio-over-Fiber system. This way, a multi-wavelength network can duplicate millimeter wave transmission systems per each wavelength and thus, multifold the capacity of the network. Finally, by introducing optical encoding/decoding, many users (depending on the code length and specifications) can simultaneously use each wavelength channel transmitting millimeter wave signal over an optical fiber link.
Feasibility and operability of the proposed system has been assessed and confirmed by software simulation. The received millimeter wave electrical signal at the receiver has been evaluated with indicators such as bit error rate (BER), eye-diagram, and signal to noise ratio (SNR). The achieved results can be used as guidelines for designing the links from base stations to the cells in 5G. The designers can benefit from the obtained results in adjusting the metrics of their designed network to predict the actual outcomes of a network. Finally, the proposed method can also contribute to the on-going efforts in optimization of millimeter wave generation methods by carefully investigating the effects of various components in the generated signal.