A new technique to optimize the properties of photonic crystal fibers supporting transmission of multiple orbital angular momentum modes

Alleviating orbital angular momentum mode coupling between two ring-cores with different materials in a photonic crystal fiber for optical communication

“…When the walk-off length between the odd and even modes is too large, the OAM mode cannot form properly. The 2π walk-off length can be calculated using equation (10) [30]:…”

Orbital angular momentum-excited surface plasmon resonance for liquid refractive index sensing by photonic crystal fiber with high sensitivity and wide detection range

“…However, when the light beam propagates in the optical fiber, dispersion in the background materials needs to be considered, i.e., the refractive index of the materials will change accordingly with the incident light wavelength. Dispersion of silica can be deduced by Sellmeier equation as follows: 36 n2−1=0.6961663λ2λ2−0.06840432+0.4079426λ2λ2−0.11624142+0.897479λ2λ2−9.8961612,where n is the refractive index of the background material silica and λ represents the wavelength of incident light. The dispersion relationship of metal materials can be obtained by the Drude model as shown in the following: 37 ε(ω)=ε∞−ωp2ω(ω+iωc),where ε(ω) is the dielectric constant of the metal, ε∞ is related to the high-frequency absorption peak, ω…”

Twisted Silica Few-Mode Hollow GeO2-Doped Ring-Core Microstructured Optical Fiber

“…. 1700 nm wavelength band (HRC MOF with a total outer diameter of 116 µm, an air core diameter of 51 µm, a ring wall thickness of 1.5 µm with ∆n = 0.12 (analogue to the Schott FBG1 glass-56.7% SiO 2 , 0.35% Al 2 O 3 , 30% PbO, 4.15% Na 2 O, and 8.65% K 2 O)) [41], 22 OAM modes at λ = 1550 nm (HRC PCF with a total outer diameter of 28 µm, an air core of 11 µm, bounded by an lanthanum optical glass ring (HIKARI LaSF09) with a wall thickness of 0.1 µm and ∆n = 0.37) [42], 436 at λ = 1550 nm with 400 modes over S + C + L bands (203 µm HRC optical fiber with 100 µm hollow highly-GeO 2 -doped-ring-core under a ring wall thickness of 1.5 µm and ∆n = 0.15) [43], 874 OAM modes at λ = 1550 nm with 514 modes over almost the entire telecommunication band (62.5 µm HRC PCF with an air core of 20 µm in diameter, bounded by the As 2 S 3 -ring with a wall thickness of 0.5 µm and an extremely high ∆n = 1.00) [44], and up to 1004 OAM modes extended over the wavelength range, covering almost all ratified telecommunication bands (O, E, S, C, L), under a record-high number of 1346 OAM modes at λ = 1550 nm (62.5 µm HRC optical fiber with 20 µm air core, bounded by As 2 S 3 -ring with a wall thickness of 0.9 µm and an extremely high ∆n = 1.00) [45].…”

“…It is obvious that previously published papers, containing not only simulations, but also the main results of tests performed to successfully fabricate the designed optical fibers, are of special interest. However, in spite of the great potential for guiding and transmitting OAM modes that HRC MOFs are declared to have [1][2][3][40][41][42][43][44][45], there are not many reports presenting properties, the results of tests, and the measured data of manufactured HRC fibers. Finally, there is a set of works, prepared by the same group of authors, that demonstrates the experimentally verified stable transmission of 12 OAM modes over a C-band along a designed and fabricated HRC optical fiber with an air core diameter of 6 µm, bounded by a ring with a wall thickness of 5.25 µm, and where ∆n = 0.03 [3,[46][47][48][49], with the following enhancing the AOM mode quantity up to 28 by enlarging the air core diameter up to 19 µm under the same ring parameters [50].…”