Modulation Index and Phase Imbalance of Dual-Sideband Optical Carrier Suppression (DSB-OCS) in Optical Millimeter-Wave System

Abstract

This paper presents a Dual-sideband Optical Carrier Suppression (DSB-OCS) technique which is used to generate an optical millimeter-wave (mm-wave) signal in radio over fiber (RoF) systems. The proposed system employs a Dual-Electrode Mach-Zehnder Modulator (DE-MZM) and a carrier of 40 GHz mm-wave for data transmission through the RoF systems. Characteristics determining the performance of the system, among which are the modulation index, phase imbalance and dispersion parameters, are included. The performance evaluations of the system show that the mm-wave signal output power follows MZM’s transfer function when the modulation index is raised. Moreover, the generated optical mm-wave signal power is affected by phase imbalance and optical splitting ratio. It is observed that the optical fiber dispersion influences the DSB-OCS system by decreasing the amplitude of the mm-wave and the signal-to-noise ratio (SNR).

Investigating the Performance of low-cost millimeter wave for long-distance Front haul RoF system based on Pre-distortion & FBG techniques

“…A single-mode fiber (SMF) and optical filter Gaussian (GOF) and an erbiumdoped fiber amplifier (EDFA) were also used to send signals to base stations (BSs). [14] illustrated the generation of (mm-wave) signal by using the Dualsideband Optical Carrier Suppression (DSB-OCS) technology in radio over fiber (RoF) systems. For data transmission across the RoF systems, the suggested system uses a Dual-Electrode Mach-Zehnder Modulator (DE-MZM) with a carrier of 40 GHz.…”

Optical Channel Selection Avoiding DIPP in DSB-RFoF Fronthaul Interface

“…This method, however, increases the complexity of the modulator system and lowers the sensitivity of the direct photodetection. A method of mitigating the influence of the DIPP was also proposed by appropriately selecting the modulation index and introducing phase imbalance in the signal modulated in the dual-sideband optical carrier suppression (DSB-OCS) format [34]. Another way to eliminate the phenomenon of deep sideband interference in the photodetector can be the introduction of interleaving light intensity modulation (IM-DD) with phase modulation (PM-DD) [35,36].…”