Orbital-angular-momentum-amplifying helical vector modes in Yb³⁺-doped three-core twisted microstructure fiber

Abstract

A helical Yb3+-doped three-core microstructure fiber (YTMF) amplifier is proposed in this paper, so as to solve the problem of generation and transmission of the orbital angular momentum (OAM) beams. The fiber is composed of three Yb3+-doped cores with a regular triangle shape and a longitudinal helical structure. The experimental results show that the 1064nm laser can be amplified due to the fluorescence amplification characteristics of the doped material Yb3+. Furthermore, theoretical analysis indicates the modes in YTMF at 1064nm, which is located in the amplified wavelength, can support nine modes carrying OAM. Therefore, the related experiments were performed and verified that the transmission modes can respectively carry 1, 2, and 3-order OAM at 1064nm in different coupling cases. These excellent properties indicate that the combination of doped materials and helical fiber provide favorable conditions for the generation and amplification of OAM, which provides a basis for the further development of OAM beams in the field of quantum communication and dense space division multiplexing.

Experimental researches and testing of silica twisted six-GeO2-doped core microstructured optical fiber. Part I: fusion splicing with telecommunication optical fibers and differential mode delay map measurements

“…Therefore, we supposed, that combination of two basic complicated fiber optic structuresmulti-core MOFs and twisted MOFswill add novel unique properties to this new type of optical fibers. Moreover, it is partially confirmed by known earlier on published papers [72][73][74][75][76] , presented results of not only simulations [73][74][75] , but also experiments 72,76 : they characterized twisted silica 2-core 73,74 and 3-core 72,75 MOFs as well as Yb-doped 3-core 76 MOFs by great potentiality for generation, guiding and amplification of OAM modes. Unlike to described above solutions, earlier on we introduced designed and successfully first time fabricated twisted MOFs 77 with 6 GeO2-doped cores (both with graded and quasi-step refractive profile indexes under profile height 0.0360 / 0.0275, respectively), outer "telecommunication" diameter 125 µm, and typical hexagonal geometry.…”

“…At the same time, there is a series of known published works [59][60][61][62][63][64][65][66][67][68][69][70][71][72] , which suppose and further confirm, based on performed both simulations and experimental researches, that induced twisting over MOFs and PCFs with specified configuration also adds new unique waveguide features. These spun, helical or twisted MOFs are declared as alternative mode converters 59 , special optical fibers for polarization maintenance and generation of optical activity [60][61][62][63] , and new kind of fiber optic electric current / magnetic field sensors 64 or twisting / strain sensors [65][66][67] as well as they are considered as new type of optical fibers with great potentiality for guiding and transmission of orbital angular momentum (OAM) modes [68][69][70][71] . Therefore, we supposed, that combination of two basic complicated fiber optic structuresmulti-core MOFs and twisted MOFswill add novel unique properties to this new type of optical fibers.…”

High sensitivity temperature sensor based on a helically twisted photonic crystal fiber

“…The relationship between the helical coordinates (ξ 1 , ξ 2 , ξ 3 ) and Cartesian coordinates (x, y, z) is described as [22,23]…”

Technological issues of twisted microstructured optical fiber fabrication

“…They are also considered as new (alternative to fiber Bragg gratings / tapered optical fibers) fiber optic probes for measuring strain and twisting [16][17][18] and sensors for measuring magnetic field and electric current [19]. Twisted or spun MOFs are also utilized as spectral and mode filters [20], optical tweezers and optical orbital angular momentum shaper in telecommunication systems, that utilize spatial division multiplexing technique [21][22][23][24][25][26][27][28][29][30][31].…”