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

Abstract

Benefiting from the rapid development of fiber-optic devices, high-speed free-space optical communication systems have recently used fiber-optic components. The received laser beam in such a system couples into single-mode fiber (SMF) at the input of the receiver module. This work is oriented to common problems in actual free-space optical coupling systems, such as atmospheric turbulence, optical system aberration, and fiber positioning error. We derive the statistical expectation models of SMF coupling efficiency with optical system aberration in the presence of atmospheric turbulence and the statistical expectation models of SMF coupling efficiency with fiber positioning error in the presence of atmospheric turbulence. The influences of optical system aberration and fiber positioning error on the coupling efficiency under different turbulence strengths are also analyzed in this paper.

The impact of optical system aberration and fiber positioning error on the FMF coupling efficiency of an FSO receiver under atmospheric turbulence

“…The statistical expectation model of the FMF's coupling efficiency is established using the wavefront matching method [24,25]. Figure 1 shows a diagram of the coupling structure in the FSO communication system, in which the FMF has FPEs.…”

“…The OSA changes the field distribution of the focused spot and reduces the FMF's coupling efficiency. In our previous work [24], we established an expectation model of the SMF's coupling efficiency under OSA condition. Herein, we extend the theoretical model to an FMF-based coupled system.…”

“…In [23], researchers used a two-mode fiber to study FMF coupling efficiency in the presence of tilt, defocus, and random angular jitter. In our previous work [24], we established a statistical expectation model of a SMF's coupling efficiency under OSA and FPE conditions, respectively. However, these studies did not consider the impact of OSA and FPE on FMF coupling efficiency in the presence of turbulence.…”

“…However, these studies did not consider the impact of OSA and FPE on FMF coupling efficiency in the presence of turbulence. In this study, we extend the model of SMF-based receiving (as described in [24]) to a 4MF-based receiving scheme, in which the statistical expectation model of the 4MF's coupling efficiency under OSA and FPE conditions is established, respectively. FMFs contain more fiber modes, and their mode field is more complex than the mode field of a SMF.…”

Spatial channel multiplexing emulation with a 21-channel multiplane plane light converter

“…Transitioning from fibre to free space optical systems has tended to build upon fibre communications systems, which release light into free space and then capture and reintroduce it into a fibre based receiver. This inevitably results in significant loss due to the wavefront degrading properties of atmospheric turbulence which prevent the light being efficiently focussed into a single mode fibre [4] [5]. Clearly multimode fibre would be more efficient [6] but would require a method of distinguishing or reintegrating numerous modes.…”