Few-Mode Fiber Coupling Efficiency for Free-Space Optical Communication

Free-space to single-mode fiber coupling efficiency with optical system aberration and fiber positioning error under atmospheric turbulence

“…c is the spatial coherence area of the incident plane wave E i,A , W 31 = W 131 h. The ratio A R /A C represents the number of speckles over the receiver aperture area, which is equivalent to the ratio of receiver diameter to the atmospheric coherence length d R /ρ c , and we can use this ratio to represent the turbulence strength [15].…”

“…where w B is mode field diameter of fundamental mode in SMF, f is the equivalent focal length of optical system, w A is the mode field radius on the pupil surface. Here, we define the parameter γ as coupling geometry parameter [15]. Figure 9 presents the relationship curve between coupling efficiency and coupling geometric parameters.…”

“…In [14], in the absence of atmospheric turbulence, the influence of the fiber positioning error on the SMF coupling efficiency is numerically evaluated based on the fieldmatching theory. Expert for SMF-based Free-space Optical Communications (FSOC) system, FMF-based FSOC system has been widely studied [15][16][17][18][19]. In [15], the authors propose a theoretical coupling model from free-space to FMF in the presence of atmospheric turbulence or random jitter, and the LP 01 mode in FMF is equivalent to the fundamental mode in SMF.…”

“…Expert for SMF-based Free-space Optical Communications (FSOC) system, FMF-based FSOC system has been widely studied [15][16][17][18][19]. In [15], the authors propose a theoretical coupling model from free-space to FMF in the presence of atmospheric turbulence or random jitter, and the LP 01 mode in FMF is equivalent to the fundamental mode in SMF. Based on the study in [15], only atmospheric turbulence is considered, the series solutions and asymptotic solutions to bit-error-rate of FMF-based FSOC system are derived for different digital combining schemes over the gamma-gamma turbulence channel in [16].…”

“…In [15], the authors propose a theoretical coupling model from free-space to FMF in the presence of atmospheric turbulence or random jitter, and the LP 01 mode in FMF is equivalent to the fundamental mode in SMF. Based on the study in [15], only atmospheric turbulence is considered, the series solutions and asymptotic solutions to bit-error-rate of FMF-based FSOC system are derived for different digital combining schemes over the gamma-gamma turbulence channel in [16]. In [17], the authors investigate the performance of a 40 Gbps Quadrature Phase Shift Keying (QPSK) FSOC system employing modes diversity and SMF coherent receipt under moderate-to-strong turbulence.…”