Adaptive SLM-based compensation of intermodal interference in few-mode optical fibers

Abstract

Transmission of optical beams with phase front vorticity through relevant distances in optical fibers poses a problem of time-dependent intermodal interference with random complex coefficients. In this paper we propose a method for compensation of interference between LP-modes, propagating through the optical fiber. To implement optical-domain modal filtering, reconfigurable diffractive optical element matched with particular modes is considered. Such an element may be encoded as phase-only hologram by means of SLM. With this approach modes can be separated spatially in the compensating diffractive element far field and handled independently with corresponding complex coefficients. Efficiency of the proposed method is confirmed by computer simulation results.

Derivation of the mode division multiplexed information transmission principles based on the spinor representation of Maxwell's equations

“…where the ˆmatrix S has symbolic representation ˆ. i t e − = H S (4) Condition (2) provides the matrix Ŝ to be unitary, so that †ˆ1 . = S S (5) Equation (5) leads to the conservation of the dot product…”

“…MDM technology is based on the utilization of the modes carrying different orbital angular momentum (OAM), which represent an additional basis of orthogonal functions for signals multiplexing [1][2][3][4]. This additional degree of freedom allows potentially the capacity of the existing optical fiber communications to be multiplexed further, so the MDM technology is considered as one of the possible ways to overcome the foreseen "capacity crunch" [5].…”

Multidiameter optical ring and Hermite–Gaussian vortices for wavelength division multiplexing–mode division multiplexing

“…31 To decouple the channels at the receiver, several methods for estimation of the channel matrix and adaptive equalization have been postulated. [32][33][34][35] Although laudable goals have been forged in experimental demonstration of MDM adopting nonconcentric rings either by multicore fibers or MEFs, these new class of optical fibers still require a compatible multimoded laser source. For OAM modes with varying diameters, to extend the work in Refs.…”