Circular Photonic Crystal Fiber Research Articles

Design of simple circular photonic crystal fiber having ultra-large negative dispersion and high birefringence for dispersion compensation

Design of simple circular photonic crystal fiber having ultra-large negative dispersion and high birefringence for dispersion compensation

Dual-channel photonic crystal fiber dual-parameter sensor exploiting surface plasmon resonance

A surface plasmon resonance (SPR) based sensor using a negative curvature circular side-polished photonic crystal fiber was proposed. The sensor’s sensitivity was analyzed using the finite element method. The impact of structural parameters was investigated. The sensor exhibits an average wavelength sensitivity (WS) of 7846 nm/RIU in the refractive index range of 1.370–1.396 and 2350 nm/RIU in the range of 1.330–1.370, with maximum WS of 46000 nm/RIU. For refractive index and magnetic field dual-parameter sensing, the simultaneously obtained magnetic field sensitivity is 0.84 nm/mT. The proposed SPR sensor demonstrates remarkable sensitivity, making it suitable for refractive index and magnetic field sensing applications.

Retraction Note: Design of circular photonic crystal fiber for OAM extraction SDM applications

Retraction Note: Design of circular photonic crystal fiber for OAM extraction SDM applications

Ethanol-infiltrated circular photonic crystal fiber for low peak power supercontinuum generation from near-infrared to mid-infrared region

Ethanol-infiltrated circular photonic crystal fiber for low peak power supercontinuum generation from near-infrared to mid-infrared region

Chalcogenide Ge20Sb5Se75 photonic crystal fiber with seven air-hole rings for ultraflat mid-infrared supercontinuum generation

Supercontinuum (SC) generation in solid-core circular photonic crystal fibers (PCFs) made of Ge20Sb5Se75 is numerically analyzed. A large core is projected to increase light coupling efficiency into selected PCFs as well as raise coupling to standard silica fibers. High nonlinear coefficient and near-zero flat dispersion allow ultraflat SC spanning 1.5–4.6 μm in an all-normal dispersion regime. This requires 3 kW of peak power with 180 fs of pulse duration. The fiber with one zero-dispersion wavelength (ZDW) generates SC bandwidth in the range of 1.54–7.39 μm at 3.5 μm using peak power of 10 kW. For the same input power, the SC spectral covers from 1.39 to 7.36 μm in 10 cm of fiber with two ZDWs. These are wider SC bandwidths than those of previous chalcogenide fibers reached with lower peak powers. Therefore, the proposed Ge20Sb5Se75 PCFs are excellent candidates for the broadband ultraflat mid-infrared SC spectra used in high-speed nonlinear imaging and frequency measurement.

Mid-infrared supercontinuum generation in As2S3-circular photonic crystal fibers pumped by 4.5 µm and 6 µm femtosecond lasers

A study on As2S3 chalcogenide photonic crystal fiber (PCF) and its potential in supercontinuum generation (SCG) applications is presented. The designed fibers exhibit near-zero flattened chromatic dispersion, facilitating coherent and broad SCG utilizing femtosecond lasers at 4.5 and 6 µm wavelengths. A continuous spectrum spanning from 1.5 to 8 µm is achieved when the initial fiber is stimulated with an input power of 20 kW. With a pulse width of 100 fs and input power of 6 kW, the second fiber provides soliton-induced SCG with 2 to 15 µm spectral bandwidth. Furthermore, the integration of these large core diameter PCFs with high-power laser pulses guarantees the preservation of optical fiber integrity without damage. Consequently, these fibers hold promise for delivering SC spectra characterized by high power density, catering to a diverse range of practical applications including optical communications, spectroscopy, sensing, metrology, and calibration.

Design and analysis of the C6H6-filled circular photonic crystal fiber with ultra-flat dispersion for broadband supercontinuum generation with peak power of 130 W and 250 W

This article introduces a new model of a circular silica-based photonic crystal fiber with a hollow core filled with C6H6. The difference in the air hole size and the distance between them in the first ring around the core has a profound effect on the dispersion, leading to ultra-flat dispersion with values as low as ±0.996 ps nm−1· km in wavelength range 0.74 µm. The high nonlinear coefficient of several 1000 W−1 · km−1 and the low confinement loss of a few tens of dB m−1 suggest proposing three fibers with dispersion and nonlinear properties suitable for broadband supercontinuum generation at low peak power. The influence of peak power on the broadening of the supercontinuum spectrum is also investigated. Fibers with a flat all-normal dispersion profile provide a smooth spectrum with bandwidths of 1.215 and 1.626 µm at 30 dB with a peak power of 250 W. A fiber with an anomalous dispersion regime generates a supercontinuous spectrum, broadening to 3.868 µm in the mid-infrared region (2.467 µm bandwidth at 30 dB) under laser pulse excitation with 130 W peak power. Our results provide further insights into the generation of broadband mid-infrared supercontinuum using liquid-core silica-fibers, which have great potential for applications in the fields of optical communications and optical sensing.

Fiber design and performance analyses for optical multiplexing: terahertz optical communications

Multiplexing is the process of combining multiple signals at a single channel. Orbital Angular Momentum (OAM) is one of the main multiplexing techniques for optical data transmissions. This paper examines and suggests a hollow core with four layers of semilunar air-hole-shaped circular photonic crystal fiber (PCF) capable of transmitting terahertz (THz) OAM information-carrying modes. By using the full vector finite element method (FEM), OAM multiplexing is analyzed for the proposed fiber. All the THz OAM-based factors are analyzed at a frequency band ranging from 400 GHz to 800 GHz. For the first time, some important PCF factors such as effective refractive index difference (ERID), dispersion profile (DP), OAM purity, confinement loss (CL), effective mode area (ERA), and numerical aperture (NA) are quantitatively discussed with applications. The proposed design supports 50 OAM modes with ERID up to 10−3. The PCF has a CL of approximately 10–10 dB cm−1 and the lowest dispersion profile is 0.3581 ps/THz/cm. Furthermore, the OAM purity is around 97%. Nonetheless, the proposed design can be used in THz-OAM transmission and high optical fiber communications.

Circular lattice benzene-core PCFs with flat near-zero dispersion for low-power broad-spectrum supercontinuum generation

A circular photonic crystal fiber infiltrated with benzene with different air-hole diameters is proposed as a new supercontinuum light source. Optical properties related to dispersion, effective mode area, nonlinear coefficient, and attenuation of the fundamental mode are investigated numerically. Two optimized structures are selected and verified against supercontinuum generation (SCG) in detail. The first structure (#F1) possesses all-normal dispersion, while the second (#F2) has a zero-dispersion wavelength. The possibility of coherent, octave-spanning SCG is proved by a 40 fs pulse, 1.064 μm wavelength, and 0.45 kW of power in-coupled into the core of #F1. Otherwise, injecting a 90 fs duration, 1.5 μm wavelength, and 0.555 kW peak power pump pulse into #F2 generates a broad SC spanning 0.76–4.23 μm. With the advantages of flat near-zero dispersion, high nonlinearity, low attenuation, and low input power used for SCG, the proposed fibers may lead to new low-cost all-fiber optical systems.

FEM analysis of a highly birefringent modified slotted core circular PCF for endlessly single mode operation across E to L telecom bands

This paper describes an exceptionally high birefringent modified slotted core circular photonic crystal fiber (MSCCPCF). At the 1.55 μm telecommunication wavelength, the proposed fiber structure aims to achieve exceptional birefringence performance through the thoughtful placement of air holes and the incorporation of slots. The optical properties of the proposed MSCCPCF are rigorously simulated using the finite element method (FEM). The FEM simulations show high birefringence of up to 8.795 × 10−2 at 1.55 μm. The suggested fiber exhibits single mode behavior in the E to L communication bands (Veff < 2.405). Numerous geometric factors and their effects on other optical properties, such as birefringence, beat length (17.62 μm) and dispersion coefficient (−310.8 ps/(nm · km)) have been meticulously studied. The proposed fiber’s viability and potential uses are evaluated by analyzing modal features like nonlinearity (21.76 W−1 km−1), confinement loss (5.615 × 10−11 dB/cm), and dispersion. The proposed fiber structure has potential for use in polarization-maintaining devices, sensors, and other photonic applications requiring high birefringence and tailored optical properties.

Numerical Investigation of Optical Properties in Carbon Tetrachloride-Filled Photonic Crystal Fibers

In this work, we design circular lattice photonic crystal fibers using Lumerical Mode Solution software, its hollow core filled with carbon tetrachloride. Optical properties including effective refractive index, chromatic dispersion, nonlinearity, and fiber loss were investigated numerically in detail based on solving Maxwell's wave equations. The small effective mode areas of only a few µm2, and confinement loss as low as 14.799 dB/m at specific pump wavelengths were obtained. It was found that near-zero ultra-flattened chromatic dispersion with fluctuations of ±0.44 ps/nm.km spans from 1300 to 1830 nm. Three photonic crystal fibers with optimal structure and features were suggested for broadband supercontinuum generation orientation.

Optical properties of circular photonic crystal fibers filled with carbon tetrachloride

In this work, the dispersion properties and nonlinear properties of circular photonic crystal fibers were improved by a combination of carbon tetrachloride infiltration into the core and modification of the air hole diameters d1 and d2 of rings in the cladding. The quantities such as dispersion, effective mode area, nonlinear coefficient, and low confinement are analyzed in detail. Based on the survey results, two photonic crystal fibers with optimal optical properties were proposed which are beneficial for supercontinuum generation. The first fiber with Ʌ = 1.0 µm, d1/Ʌ = 0.6, has an all-normal dispersion of –10.785 ps/nm.km at a pump wavelength of 0.985 µm. The high nonlinear coefficient of 581.795 W–1.km–1 and the low confinement loss of 3.904 dB/m are also achieved with this fiber. SC broadband under the influence of soliton is expected to be generated when using the second fiber (Ʌ = 2.0 µm, d1/Ʌ = 0.3) with flat and low anomalous dispersion at the pump wavelength of 1.3 µm.

Design of New Photonic Crystal Fiber for Orbital Angular Momentum Modes Transmission

In order to achieve the flexibility and miniaturization of orbital angular momentum (OAM) fiber coupler, it is necessary to continuously design and optimize the base fiber to cooperate with the efficient transmission of multiplexed beam. It is more advantageous to use the photonic crystal fiber (PCF) instead of ring fiber in the coupler design. We have proposed a new fiber based on circular PCF structure to support high performance OAM modes transmission. The optimal parameters are selected to realize the stable transmission of 4 OAM mode groups with high mode quality. In the wavelength range of 1.2 μm∼2.0 μm, the confinement loss of low order mode is less than 10−8 dB/m, and the mode purity is more than 81.7%. Because of its flexible structure and low loss characteristics, the proposed OAM fiber can be widely used in the design of optical fiber devices in modular division multiplexing (MDM) communication systems.

A novel graphene-based circular dual-core photonic crystal fiber pressure sensor with high sensitivity

A novel graphene-based circular dual-core photonic crystal fiber pressure sensor with high sensitivity

Supercontinuum spectra above 2700 nm in circular lattice photonic crystal fiber infiltrated chloroform with the low peak power

Supercontinuum spectra above 2700 nm in circular lattice photonic crystal fiber infiltrated chloroform with the low peak power

Design and analysis of a hexagonal circular photonic crystal fibre with ultra-high negative dispersion and low confinement loss

This paper proposes a Hexagonal Circular Photonic Crystal Fiber (HC-PCF) with uniform tiny air holes around the core, obtaining ultra-high negative dispersion, high Birefringence and low confinement loss. The modal properties of the HC-PCF are investigated using the full-vectorial-Finite Element Method (FEM) with a perfectly matched layer as the boundary condition. The numerical investigations show ultra-high negative dispersion of −25503 ps/nm.km, a birefringence of 1.36×10-2, a nonlinearity of 38.34w-1km-1 and a confinement loss of 4.95×10-3 dB km-1 at the wavelength of 1550 nm. Moreover, the proposed HC-PCF exhibits a high negative dispersion and multiple Zero Dispersion within the 800 to 2000 nm wavelengths range. Specifically, the high negative dispersion, low optical Confinement Loss, and multiple Zero Dispersion Wavelengths (ZDW) give the proposed HC-PCF high Power Spectral Density (PSD). These characteristics make the proposed fibre suitable for long-range telecommunication networks and optical sensing.

Design and numerical analysis of a circular SPR based PCF biosensor for aqueous environments

This paper presents the design and numerical analysis of a circular photonic crystal fiber (PCF) biosensor based on surface plasmon resonance (SPR) for aqueous environments. The proposed biosensor has a geometrical design that uses the cladding at the fiber's exterior to simplify the gold and analyte deposition process. The sensing characteristics and performances of the proposed biosensor are fully investigated with the finite element method. The investigation indicates that the plasmonic material's thickness affects the biosensor's performance. The results of the proposed biosensor demonstrate a wide refractive index range of 1.30 to 1.44, with the highest wavelength or spectral sensitivity as 21,000 nm/RIU and the highest resolution as 9.09×10−6 RIU. The proposed biosensor has a straightforward geometric profile. The proposed biosensor is stable and suited for aqueous surroundings and wide-range detection applications.

High-performance surface plasmon resonance fiber sensor based on cylindrical vector modes

Cylindrical vector modes with azimuthal polarization and low transmission loss are proposed for the first time to be utilized in a novel design of a surface plasmon resonance (SPR) sensor based on a circular photonic crystal fiber (C-PCF). A C-PCF with a ring of air holes in the cladding is designed where a gold layer with a thickness of 44 nm is coated on the outer cladding surface. The optimal geometric parameters are determined using the finite-element method (FEM) for a high-quality TE01 mode and high sensitivity of the sensor. The proposed SPR sensor shows high sensitivity for analyte refractive index (RI) ranging from na = 1.29 to 1.34 over the wavelength range of 1400–2000 nm. It is expected that the proposed sensor can sense low concentrations of hemoglobin, lymphocytes and monocytes of red and white blood cells which are effective in diagnosing the progress of cancer tumors. The maximum sensitivity of 13,800 nm/RIU is obtained in the refractive index environment of 1.33–1.34. The sensor resolution is of the order of 10−6 and the amplitude sensitivity reaches its maximum of 2380 RIU−1 at na = 1.30 which is the highest value ever reported. Our proposed sensor shows high sensitivity and simultaneously simple design with high performance.

Flat-top and broadband supercontinuum generation in CCl4-filled circular photonic crystal fiber

In this work, a flat-top and broadband supercontinuum (SC) generation in photonic crystal fibers (PCFs) infiltrated with carbon tetrachloride (CCl[Formula: see text] with different air hole diameters in the cladding has been introduced. The optical properties of the fundamental mode are analyzed by numerical simulation. Based on the obtained results, two optimized PCFs with small dispersion are proposed and verified against SC generation in detail. The first fiber has an all-normal dispersion of [Formula: see text]9.376[Formula: see text]ps.nm[Formula: see text].km[Formula: see text] at the pump wavelength of 0.98[Formula: see text][Formula: see text]m, generating broadband of 768[Formula: see text]nm and flat-top with only 0.3[Formula: see text]nJ of input energy and time duration of 90[Formula: see text]fs. In the meantime the dispersion property of the second fiber is anomalous, which equals 1.105[Formula: see text]ps[Formula: see text][Formula: see text][Formula: see text]nm[Formula: see text][Formula: see text][Formula: see text][Formula: see text]km[Formula: see text] at 1.3[Formula: see text][Formula: see text]m pump wavelength. The second fiber generates a SC spectrum of 1,751.1[Formula: see text]nm with input energy and time duration of 0.55[Formula: see text]nJ and 55[Formula: see text]fs, respectively. Proposed fibers are suitable for all-fiber SC sources which could lead to new low-cost all-fiber optical systems.

An ultra-flattened chromatic dispersion in circular C6H6-infiltrated photonic crystal fibers

An ultra-flattened chromatic dispersion in circular C6H6-infiltrated photonic crystal fibers