Mode Conversion Between Beams Carrying Orbital Angular Momentum With Opposite Topological Charges Using Two-Dimensional Multimode Interference Waveguides

Year: 2023

Authors: Soltani A., Firouzeh ZH., Mousavi SF., Nezhad AZ., Nouroozi R.

Autors Affiliation: Isfahan Univ Technol, Dept Elect & Comp Engn, Esfahan 8415683111, Iran; Univ Trieste, Dept Phys, I-34127 Trieste, Italy; CNR INO, Natl Inst Opt, I-50125 Florence, Italy; Inst Adv Studies Basic Sci, Dept Phys, Zanjan 66731, Iran.

Abstract: Recently, the implementation of rectangular waveguides for generation and manipulation of orbital angular momentum (OAM) modes, has been developed to exploit the outstanding features of these modes in more complex integrated devices. Multimode interference (MMI) structures have been widely used in both one and two dimensions as the basic elements in many integrated optical devices like optical beam splitters, mode converters, couplers, wavelength-division (de)multiplexers, and switches. According to the various applications of OAM modes in quantum and classical communications, the study of their propagation properties in MMI waveguides is useful in order to facilitate the way into higher security and capacity systems. This paper presents the results of numerical investigation of a proposed integrated optical OAM mode converter which is performed based on the mode decomposition properties of propagating OAM modes in 2D MMI waveguides, as well as the fact that any order of OAM mode can be represented as superposition of an odd mode and a quarter-wave shifted even mode. The proposed device, which consists of two MMI waveguides connected by phase shifters and linear waveguides, provides mode conversion between beams carrying OAM with odd opposite topological charges. The design procedure is performed for OAM modes with topological charge values of l = +/- 1 and l = +/- 3 using beam propagation method. The proposed device is passive with reciprocal behavior and has the output mode purity of 94% and 82% for beams carrying l = +/- 1 and l =+/- 3, respectively.

Journal/Review: JOURNAL OF LIGHTWAVE TECHNOLOGY

Volume: 41 (7)      Pages from: 2179  to: 2184

KeyWords: Optical waveguides; Optical beams; Interference; Phase shifters; Optical device fabrication; Arrayed waveguide gratings; Orbits; Mode conversion; OAM; topological charge; two-dimensional MMI structures
DOI: 10.1109/JLT.2022.3225820

ImpactFactor: 4.100
Citations: 3
data from “WEB OF SCIENCE” (of Thomson Reuters) are update at: 2024-11-24
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