Fiber-Coupling Efficiency of Laser Array Beam from Turbulent Atmosphere to Fiber Link

Gökçe M. C., Baykal Y., Ata Y.

Journal of Lightwave Technology, vol.41, no.1, pp.59-65, 2023 (SCI-Expanded) identifier

  • Publication Type: Article / Article
  • Volume: 41 Issue: 1
  • Publication Date: 2023
  • Doi Number: 10.1109/jlt.2022.3204559
  • Journal Name: Journal of Lightwave Technology
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, PASCAL, Aerospace Database, Communication Abstracts, Compendex, INSPEC, Metadex, Civil Engineering Abstracts
  • Page Numbers: pp.59-65
  • Keywords: Atmospheric turbulence, fiber coupling efficiency, laser array beam, laser beam transmission, optical communication, single mode fiber
  • TED University Affiliated: Yes


IEEEFree-space optical communication (FSOC) systems are nowadays integrated with fiber optical components developed for fiber-optic communications. In such integrated systems, the collected portion of the incident beam on the receiver lens is coupled into a single-mode fiber. The process of coupling, however, is mostly affected by the atmospheric turbulence which distorts the coherency of the propagating beam i.e., it results in speckle over the coupling lens causing a reduction in the coupling efficiency. In this paper, we aimed at investigating the fiber coupling efficiency of laser array beams propagating in a turbulent atmosphere. For this purpose, using the Huygens-Fresnel principle, mutual coherence function (MCF) for a laser array beam incidence is formulated. In this way, the average power coupled into the fiber and the average received power on the coupling lens are derived for a laser array beam incidence. It is found that the fiber coupling efficiency clearly increases with the increase in ring radius and the number of Gaussian beams in the array and rapidly decreases with increasing structure constant of atmosphere, link distance, and the number of speckles over the receiver aperture. We also demonstrate the effect of various FSOC system parameters on the coupling efficiency.