Relaying System Based on Few-Mode EDFA for Space Division Multiplexing Wireless Optical Communication

Abstract

Relay assisted transmission can compensate atmospheric turbulence, improve transmission distance, and realize communication between non-linear targets in free space optical communication (FSO) system. Space division multiplexing (SDM) greatly improves the channel capacity of FSO system. This paper focuses on the relay assisted transmission oriented to SDM wireless optical communication system. We develop a dual-hop SDM FSO communication model with two spatial mode channels. At the relay, the received optical signals are amplified by the few mode EDFA and forwarded to the destination. Simulation results show that the bit error rate (BER) of the dual-hop SDM system with a few mode EDFA based relay outperforms the single-hop SDM system. Under BER = 𝟏 × 𝟏𝟎 −𝟓 , the power budget is increased by 0.53𝒅𝑩, 1.2 𝒅𝑩, and 4.88 𝒅𝑩, when 𝑪 𝒏 𝟐 = 𝟒 × 𝟏𝟎 −𝟏𝟓 , 𝟕 × 𝟏𝟎 −𝟏𝟓 and 𝟏 × 𝟏𝟎 −𝟏𝟒 , respectively. Moreover, the BER performance is the best when the relay is (originally in the middle of the link) slightly closer to the source. .

Free Space Optical Communication: An Enabling Backhaul Technology for 6G Non-Terrestrial Networks

“…They used the generalized gamma distribution to model the propagation of OAM modes through atmospheric turbulent FSO channels and derived closed-form expressions for various performance metrics. Cui et al [189] focused on relay-assisted transmission in SDM wireless optical communication systems. They developed a dual-hop SDM FSO communication model and demonstrated that the BER of the dual-hop SDM system with a few-mode EDFA-based relay outperformed the single-hop SDM system.…”

Analysis of OAM Modes and OFDM Modulation for Outdoor Conditions

“…In (Raza et al, 2023), LG00 and LG01 modes were multiplexed to increase the system bandwidth using intensity modulation. In (Cui, Cai, and Zhang, 2022), 2-hop free space optics (FSO) transmission was established using LP01 and OAM+1 modes, facilitated by a few modes' fiber relays at 1550nm. In (Badavath et al, 2023), 3-bit depth grayscale images are transmitted on three LG beams through FSO and retrieved using a convolutional neural network on speckle distributions.…”