Improved passive optical network RoF system based vertical cavity-surface emitting laser (VCSEL) optical source external modulation

Abstract

Passive Optical Network (PON) is a promising 5 G optical fiber network technology, that can enhance reliability data rate, and bandwidth saving. This simulation-based study investigates the feasibility of implementing a vertical cavity-surface emitting laser (VCSEL) optical source along with wavelength-division multiplexing (WDM) for designing a PON radio over fiber (RoF) system that can authorize multi-subscribers, users, to simultaneously use the same optical fiber for Front long-haul data transmission. Three scenarios are proposed: First, a VCSEL, and a Mach–Zehnder Modulator with a distinctive frequency are made accessible to every user in the PON system. Whereas, in the second scenario, a continuous wave (CW) laser is used to replace the VCSEL in the same PON. 16 users are multiplexed by a WDM and transmitted over a link length of 200 km. The system performance is, thus measured in terms of Q-factor, and it is revealed that the VCSEL-based system outperforms the system utilized CW laser to a distance of 150 km, with a maximum gain in the Q-factor of about 4.5. Both postulated systems are able to achieve a maximum transmission distance of 180 km with a minimum Q-factor of 6. Moreover, to minimize, the input current of around 1 mA and the system complexity, a third scenario is presented in which one VCSEL with 193.1 THz is shared among multiple users. The Q-factor performance is then simulated for up to 72 users, revealing that the minimum level of acceptable Q-factor has been maintained up to a link length of 180 km.