A 400 Gbps/100 m free-space optical link

Abstract

A 400 Gbps/100 m free-space optical (FSO) link with dense-wavelength-division-multiplexing (DWDM)/space-division-multiplexing (SDM) techniques and a doublet lens scheme is proposed. To the best of our knowledge, this is the first time that a link adopting DWDM and SDM techniques and a doublet lens scheme has demonstrated a 400 Gbps/100 m FSO link. The experimental results show that the free-space transmission rate is significantly enhanced by the DWDM and SDM techniques, and the free-space transmission distance is greatly increased by the doublet lens scheme. A 16-channel FSO link with a total transmission rate of 400 Gbps (25 Gbps/λ × 16 λ = 400 Gbps) over a 100 m free-space link is successfully demonstrated. Such a 400 Gbps/100 m DWDM/SDM FSO link provides the advantages of optical wireless communications for high transmission rates and long transmission distances, which is very useful for high-speed and long-haul light-based WiFi (LiFi) applications.

WDM Free-Space Optical Communication System of High-Speed Hybrid Signals

“…A DWDM-FSO communication system that uses a multi-beam with the space division multiplexing (SDM) technique [15] can be a succedaneum for the proposed WDM-FSO communication system, which transmits hybrid signals through the doublet lens scheme (Fig. 2).…”

“…In addition, the WDM channels that are modulated with different signals are proposed by using only simulated results [10]- [14]. The optical lens for the multi-beam WDM-FSO increase with the number of WDM channels, thereby considerably increasing the cost of the network [6]- [9], [15]- [17]. This study demonstrates a WDM-FSO communication system that transmits hybrid signals, wherein four wavelengths are modulated with various high-speed signals using a single beam.…”

Frequency-division multiplexer and demultiplexer for terahertz wireless links

“…It is interesting to note the contrast with free-space optical (FSO) networking, another feasible approach to achieving wireless links with Tb/s throughput. FSO links can also employ frequency multiplexing, and like a THz link, the signals propagate as directional beams, not omnidirectional broadcasts 41 . However, the wavelength-dependent diffraction effects described here would not be expected to manifest themselves in FSO systems.…”

“…The relevant parameter here, to determine the significance of diffraction effects, is the spacing between adjacent frequency channels d v , as a fraction of the average carrier frequency v 0 . In a typical frequency-multiplexed FSO system 41 , this fractional spacing d v / v 0 is quite small, on the order of 10 −4 . In contrast, for our system demonstration (Fig.…”

A High-Speed and Long-Reach PAM4 Optical Wireless Communication System

“…In addition, doublet lenses can be adopted as a substitute for afocal telescopes to reduce the divergence of laser beam and extend the free-space transmission distance. Other previous study demonstrated a 400 Gbps/100 m FSO link with dense-wavelength-division-multiplexing (DWDM) and space-division-multiplexing (SDM) schemes [7]. A 16-parallel 25-Gbps FSO link with an overall data rate of 400 Gbps over a 100-m free-space transmission is illustrated.…”