Free Space Optical Communication in Long-Reach Unidirectional Ring-Architecture Fiber Network

Chien-Hung Yeh,Chi-Wai Chow,Wei-Yao You,Jhao-Ren Chen,Wen-Piao Lin

doi:10.1109/access.2020.3020822

Abstract

In the work, a ring-constructed wavelength-division-multiplexing (WDM) access system for delivering multiple free space optical (FSO) wireless signals is investigated. To reach the FSO transmission through single-mode fiber (SMF) connection, the optical wireless unit (OWU) and remote OWU are designed in the WDM network. The downstream and upstream WDM FSO channels could be transmitted in unidirectional propagation with the same wavelength. Hence, the presented ring-based WDM network not only can transmit the FSO signal, but also can circumvent the Rayleigh backscattering (RB) interferometric beat noise. In addition, according to the experimental results, the SMF and FSO transmission lengths can reach 50 km and 500 to 1000 m at the forward error correction (FEC) level without using optical amplification and dispersion compensation, respectively, when four WDM wavelengths are exploited experimentally for demonstration.

Highlights

To comply with the ultra-broadband demands of end-user in the last mile communication network, utilizations of the 5G/B5G wireless network, visible light communication (VLC), free space optical (FSO) communication and passive optical network (PON) have been studied in recent years [1]–[5]
The WDM-FSO downstream channels would launch into the optical wireless unit (OWU) and drop the corresponding downstream WDM wavelength for FSO transmission
The WDM-FSO downstream wavelength could be decoded in each remote OWU (ROWU) from the corresponding OWU

Summary

Introduction

To comply with the ultra-broadband demands of end-user in the last mile communication network, utilizations of the 5G/B5G wireless network, visible light communication (VLC), free space optical (FSO) communication and passive optical network (PON) have been studied in recent years [1]–[5]. According to the obtained power sensitivity experimentally and the simulation results, the four downstream and upstream WDM FSO signals can support the free space link length from 500 to 1000 m without optical amplification after 50 km SMF connection under the forward error correction (FEC) threshold.

Results

Conclusion