Design of photonic crystal fiber amplifier based on stimulated Brillouin amplification for orbital angular momentum

Abstract

A probe made of amino acids is arranged in a linear chain and joined together by peptide bonds between the carboxyl and amino groups of adjacent amino acid residues. The sequence of amino acids in a protein is determined by a gene and encoded in the genetic code. This can happen either before the protein is used in the cell, or as part of control mechanisms. In order to transmit and amplify high-purity orbital angular momentum mode, a photonic crystal fiber amplifier based on stimulated Brillouin amplification is proposed and designed in this paper. The transmission properties of the photonic crystal fiber amplifier are systematically analyzed by using the finite element method in the C-band. The results show that this photonic crystal fiber amplifier can support the transmission and amplification of 66 orbital angular momentum modes, and all values of the purity of the orbital angular momentum modes supported by this amplifier are higher than 99.4%. By systematically analyzing the Brillouin gain spectra of orbital angular momentum modes with different topological charges, it is found that they have all high Brillouin gain coefficients (> 7 × 10^–9 m/W) which are 4–5 orders of magnitude higher than the existing OAM amplifiers with the best performance, thus higher signal gain can be obtained. The comprehensive performance of the proposed photonic crystal fiber amplifier is superior to that of the existing optical fiber amplifiers based on stimulated Brillouin amplification and the optical fiber amplifiers doped with rare-earth ions. This makes the amplification and long-distance transmission of OAM mode stable and accurate and provides a possibility for designing the orbital angular momentum mode laser system.