CSI Extraction using Double Cross-Gain Modulation of Optical Amplifiers for Pre-compensated Free Space Optical

In high-speed Free-Space Optical (FSO) mobile backhauling, we present a novel Tx-CSI extraction method. Using Cross-Gain Modulation (XGM) in Erbium-Doped Fiber Amplifier (EDFA), with polarizations and pulse trains, we ensure robust SNR for extracted Tx-CSI. Validated through theoretical analysis and 20Gbps PAM4 FSO transmission, it enhances seamless FSO communication and addresses channel control needs in mobile backhauling.