Coherent Optical Communication

Effect of Wavefront Distortion in Non-Kolmogorov Turbulence on the Performance of Multi-Beam Transmission Coherent Detection

“…where A l , ω l , and ϕ l are the local oscillation light amplitude, angular frequency, and phase, respectively. Then, the power of the output intermediate frequency (IF) signal through the detector is given by the equation [1]:…”

“…Numerical simulations are p formed to combine Equations ( 23) and (24) for the variation relationship between the m ing efficiency and BER of the coherent detection system during oblique range transm sion. Simulation conditions are set as follows [1]: wavelength λ = 1550 nm, electron cha e = 1.6 × 10 -19 C, quantum efficiency of the detector η = 0.8, Planck constant h = 6.63 × 1 Js, carrier frequency v = 1.94 × 10 14 Hz, the number of photons received within a sin Figures 2a,b show the variation in the mixing efficiency and BER of the coherent tection system with the spectral power-law exponent α under the conditions of the atm pheric turbulence slant propagation. Figures 2a,b show that with the increase in the sp tral power-law exponent α, the mixing efficiency of the coherent detection system te to decrease, and the BER tends to increase; the number of signal beams increases, the m ing efficiency of the coherent detection system at the receiving end increases, and the B gradually decreases.…”

“…Numerical simulations are performed to combine Equations ( 23) and (24) for the variation relationship between the mixing efficiency and BER of the coherent detection system during oblique range transmission. Simulation conditions are set as follows [1]: wavelength λ = 1550 nm, electron charge e = 1.6 × 10 mitted by the transmitting end increases, when passing through the atmospheric tur lence slant path link, the wavefront is superimposed, and it can partially compensate the decrease in mixing efficiency and increase in BER of the coherent detection system the receiving end as the Fresnel zone (λL) 1/2 increases.…”

“…The optical wireless coherent communication system adopts the coherent detection method, which has a detection sensitivity of about 20 dB gain compared with the traditional direct detection method and is more suitable for long-distance communication [1]. However, during long-distance transmission the signal beam is disturbed by turbulence and fluctuates randomly, which leads to a decrease in the efficiency of coherent detection at the receiving end, and the communication quality cannot be guaranteed [2].…”