Fiber-coupling efficiency of Gaussian Schell model for optical communication through atmospheric turbulence

Abstract

In practice, due to the laser device and the inevitable error of the processing technique, the laser source emitted from the communication terminal is partially coherent, and is represented as a Gaussian Schell model (GSM). The cross-spectral density function based on the Gaussian model in previous research is replaced by the GSM. Thus the fiber-coupling efficiency equation of the GSM laser source through atmospheric turbulence is deduced. The GSM equation presents the effect of the source coherent parameter ζ on the fiber-coupling efficiency, which was not included previously. The effects of the source coherent parameter ζ on the spatial coherent radius and the fiber-coupling efficiency through atmospheric turbulence are numerically simulated and analyzed. The result manifests that the fiber-coupling efficiency invariably degrades with increasing ζ. The work in this paper is aimed to improve the redundancy design of fiber-coupling receiver systems by analyzing the fiber-coupling efficiency with the source coherent parameters.

Free-Space to Fiber Coupling of Electromagnetic Gaussian Schell-Model Beams in Turbulent Marine Atmospheric Channel

“…The influence factors on coupling efficiency such as beam properties, turbulence level and lens size are discussed in details. Unless otherwise indicated in figures, the parameters used for simulations have typical values as follows [6], [8], [13]: Considering the two significant properties (i.e., coherence and polarization) of EGSM beam, the relationships between coupling efficiency η and beam transverse coherent widths δ xx , δ yy are analyzed in Fig. 2 first.…”

“…When a beam propagates in free space, diffraction broadening occurs. In the absence of turbulence, the increment of beam spatial coherence with diffraction broadening causes the rise of η [6]. But in practical atmospheric link, turbulence is inevitable, which reduces beam coherence and in turn η during propagation.…”

“…Liu et al discussed the wave-front aberrations of a plane wave caused by terrestrial atmospheric turbulence, including their impacts on fiber coupling efficiency and correction methods [5]. Tan et al considered the influence of source coherence, and extended their investigation to partially coherent Gaussian Schell-model beams [6]. Wright et al gave a demonstration of fiber coupling of Gaussian laser beam in a low Earth orbiting space to ground channel by use of an adaptive optical correction system [7].…”

Enlarging field of view in free space optical signal receiver via pump and signal combiner

“…1 On the other hand, after the laser beam has been emitted by a distant transmitter, its optical axis will drift randomly because of mechanical vibration and atmospheric turbulence. Therefore, the coupled laser in the receiver will easily escape from the core of SMF and result in a low coupling efficiency [7][8][9][10] . To obtain a higher and more stable coupling efficiency, adaptive *Corresponding author, e-mail: w_zt@163.com optics has been verified an effective scheme and has been commonly used in optical signal receiver.…”

Investigation on the Coupling of Vortex Beam Into Parabolic Fiber in Turbulent Atmosphere

“…Traditional fiber coupling of free-space beams is based on single-mode fiber and investigated extensively. The basic model for coupling was established and the coupling efficiencies of different beams were analyzed, such as plane wave and Gaussian beam [2]- [4]. The coherence and polarization of beam source were also considered in coupling [5].…”