mm-wave Generation Using Unbalanced Mach-Zehnder Modulator and Optical Frequency Comb Source for DWDM Optical Network

This paper demonstrating a successful photonics generation of 60GHz millimeter-wave by quadrupling a 15GHz RF signal with an unbalanced Mach-Zehnder modulator (UMZM). With a 4ps delay between the two arms of UMZM and by controlling the modulation index of UMZM, only two side bands can be generated along with the main carrier, which is suppressed by a band pass filter. Hence, a millimeter-wave of 60GHz is generated with a total suppression of undesired low/high-order harmonics. Moreover, an optical comb with spacing of 30GHz is generated using a cascade of intensity and phase modulators and utilized for an optical wavelength-division multiplexing (WDM) transmission system at data rate of 5Gbps for each user. Results show that the system maintains good bit error rate performance up to a receiver sensitivity of −22dBm.

I. Introduction

Due to the large demand for high-speed data, wireless technology has been developing different generations of technology from 1G to 4G [1], and yet the demand is still not fulfilled. Recently, researchers started working on a highspeed technology known as 5G, which is supposed to operate on a millimetre-wave (mm-wave) band of 30GHz-300GHz. Millimetre-wave signals cannot travel for a long distance, and that makes 5G technology suitable for indoor use. Therefore, an optical fiber is needed to carry the user's data between the base stations [1]. For this reason, generating mm-wave signals is more appropriate and has been widely studied in the electrical domain, unfortunately it's more expensive and noisy. Therefore, photonic generation of mm-wave signals is widely studied, with different methods were implemented experimentally.