Birefringent Photonic Crystal Fiber Research Articles

Highly birefringent hexagonal porous core photonic crystal fiber for polarization maintaining integrated THz-photonics applications

Highly birefringent hexagonal porous core photonic crystal fiber for polarization maintaining integrated THz-photonics applications

A sensitive methane gas sensor based on sagnac interferometer with a cryptophane-A film-coated birefringent photonic crystal fiber : design and FEM simulation

As being sensitive to methane gas, cryptophane-A is widely used in fiber optic methane gas sensors. In order to further improve the sensitivity, a Sagnac interference (SI) was constructed with a cryptophane-A film coated birefringent photonic crystal fiber (PCF) to realize the methane gas sensing. Cryptophane-A film absorbs the methane gas and as a result its refractive index decreases linearly with the increasing of methane gas concentration. Simulation results utilizing the finite element method demonstrate that sensitivity reaches 124.4 nm/% when the methane concentration ranges from 0% to 3.5%. The sensor is relatively simple to prepare and can achieve high sensitivity, which has potential application in the field of monitoring methane gas leakage.

Enhanced sensitivity of temperature sensor by a novel birefringent photonic crystal fiber with PDMS filling

It is more than important to sensitively take the temperature in industrial production and experimental study. In this paper, the high-sensitivity temperature sensor based on high birefringent photonic crystal fiber is proposed. To increase the sensitivity, polydimethylsiloxane (PDMS) was filled into the internal elliptical air hole of the photonic crystal fiber (PCF) to propose the PDMS/silica hybrid PCF structures. Temperature is measured by the quantitative change in birefringence of the refractive index of the PDMS material with temperature. We designed it as a detection loop and obtain the temperature detection sensitivity of up to 8.01 nm/°C in the range of −20 °C–20 °C, which was 6.5 times higher compared to the sensitivity obtained by filling with ethanol. This enables the designed PCF temperature sensor to be used for real-time and accurate temperature monitoring in the fields of bio-detection, chemistry, pharmaceuticals, etc.

Broadband dispersion compensation and high birefringence photonic crystal fiber for CWDM/DWDM networks

In this study, we propose a new design based on photonic crystal fibers (PCFs) for broadband dispersion compensation in telecommunication networks. The proposed design has a hexagonal structure arrangement of air-holes rings of different diameters between the silica core and the cladding. The PCF properties like effective area, nonlinearity, dispersion slope, confinement loss, and birefringence are reported and discussed. For the best performance we present three designs A, B and C. Simulation results show that the three designs cover the six-telecommunication optical bands O-, E-, S-, C-, L- and U- bands (wavelengths ranging from 1260 to 1675 nm). Design A achieves a large negative dispersion value of about − 1716 ps/(nm.km) with relative dispersion slope equals to that of conventional single-mode optical fibers (SMFs) of about 0.0036 nm−1, which makes it very suitable for long-haul DWDM transmission systems. With a little modification in the core, designs B and C achieve much higher confinement ability and achieve a very large birefringence value for polarization mode dispersion and sensing applications. Design C is engineered to have exact opposite dispersion of SMF with zero dispersion at the wavelength 1310 nm, which makes it a promising design in CWDM transmission system. The numerical values have been investigated using the full vector finite element method.

Highly birefringent photonic crystal fibers with near-zero flattened dispersion for polarization-maintaining terahertz transmission

In this work, we present a novel hexagonal lattice porous-core photonic crystal fiber (PCF) exhibiting high birefringence, low loss, and near-zero flattened dispersion in the terahertz regime. The core design incorporates asymmetric rectangular and triangular air holes to achieve enhanced birefringence performance. The background material, TOPAS, is carefully selected to minimize dispersion and transmission losses. Furthermore, by employing the finite element method, the guiding properties of the proposed PCF are comprehensively investigated. Our simulation results reveal a near-zero flattened dispersion value of ±0.2ps⋅THz−1⋅cm−1 within a broad frequency range of 0.8−1.6THz, accompanied by an impressive birefringence value of 0.072. Additionally, the PCF demonstrates outstanding characteristics in terms of confinement loss, effective material loss, effective mode area, core power fraction, and bending loss. Considering its exceptional attributes, the proposed PCF holds significant promise for polarization-maintaining applications and terahertz communication systems.

Compact simultaneous label-free autofluorescence multi-harmonic microscopy for user-friendly photodamage-monitored imaging.

Label-free nonlinear optical microscopy has become a powerful tool for biomedical research. However, the possible photodamage risk hinders further clinical applications. To reduce these adverse effects, we constructed a new platform of simultaneous label-free autofluorescence multi-harmonic (SLAM) microscopy, featuring four-channel multimodal imaging, inline photodamage monitoring, and pulse repetition-rate tuning. Using a large-core birefringent photonic crystal fiber for spectral broadening and a prism compressor for pulse pre-chirping, this system allows users to independently adjust pulse width, repetition rate, and energy, which is useful for optimizing imaging conditions towards no/minimal photodamage. It demonstrates label-free multichannel imaging at one excitation pulse per image pixel and thus paves the way for improving the imaging speed by a faster optical scanner with a low risk of nonlinear photodamage. Moreover, the system grants users the flexibility to autonomously fine-tune repetition rate, pulse width, and average power, free from interference, ensuring the discovery of optimal imaging conditions with high SNR and minimal phototoxicity across various applications. The combination of a stable laser source, independently tunable ultrashort pulse, photodamage monitoring features, and a compact design makes this new system a robust, powerful, and user-friendly imaging platform.

Continuous tuning of pulse parameters in a soliton fiber laser by adjusting the effect ofnonlinear polarizationrotation.

We demonstrate that through inserting a short length of highly birefringent small-core photonic crystal fiber (Hi-Bi SC-PCF) into a soliton fiber laser, the nonlinear polarization rotation effect in this laser can be manipulated, leading to continuous tuning of the output pulse parameters. In experiments, we observed that by adjusting the polarization state of light launched into the Hi-Bi SC-PCF and varying the cavity attenuation, the laser spectral width can be continuously tuned from ∼7.1 to ∼1.7 nm, corresponding to a pulse-width-tuning range from ∼350 fs to ∼1.56 ps. During the parameter tuning, the output pulses strictly follow the soliton area theory, giving an almost constant time-bandwidth-product of ∼0.31. This soliton fiber laser, being capable of continuous parameter tuning, could be applied as the seed source in ultrafast laser systems and may find some applications in nonlinear-optics and soliton-dynamics experiments.

Research of highly birefringent photonic crystal fibers based on elliptical core arrays

Research of highly birefringent photonic crystal fibers based on elliptical core arrays

High birefringence photonic crystal fiber for glucose sensing

This paper focuses on designing a simple photonic crystal fiber (PCF) biosensor. The proposed glucose sensor is modelled by Lumerical software using the finite element method. To evaluate the efficiency of this model, different sensing properties such as birefringence, coupling length, and relative sensitivity are calculated at different air-filling fractions. The principle of this PCF is to detect the variations in the refractive index of the different concentration glucose solutions. The analyte will be injected into an elliptical channel surrounded by two rings of air holes in a hexagonal shape. Numerical simulations show that increasing the air-filling fraction yields high performance and more light confinement. At the air-filling fraction of 0.45, the maximum birefringence and relative sensitivity were 4.01 × 10−3 and 91%, respectively. Also, the coupling length reaches a minimum of 162.09 μm.

A highly birefringent photonic crystal fiber based on a central trielliptic structure: FEM analysis

In this study, a highly birefringent photonic crystal fiber (PCF) with a simple center trielliptic is presented. The finite element method is applied in this study to analyze PCF. By adjusting the ellipticity and other parameters, the fiber performances can be optimized. As the parameters of the PCF are finalized, i.e., the number of cladding N = 4, lattice constant Λ = 1.6 μm, and ellipticity η = 2, a high birefringence of 3.56 × 10−2 can be obtained at the wavelength λ = 1.55 μm . Moreover, the dispersions of the X- and Y-polarized modes are relatively flat in the range of 1 μm to 1.55 μm along with a confinement loss as low as 9.63 × 10−6 dB m−1. Besides, this structure has demonstrated remarkable robustness, maintaining its superior performance even when subjected to significant displacements or rotations. Due to the characteristics of the high birefringence and low confinement loss, this PCF can be used for long distance optical fiber communication, fiber sensing, dispersion compensation, and supercontinuum generation.

A highly birefringent and compact nonlinear photonic crystal fiber for next-generation optical fiber applications: design and investigation

A highly birefringent and compact nonlinear photonic crystal fiber for next-generation optical fiber applications: design and investigation

Detection of critical cancer cells in human organs using dual demodulation photonic crystal fiber: Numerical study

This study reports a novel approach for early detection of malignant cancer cells in human organs using a birefringent photonic crystal fiber (PCF)-based optical sensor with dual demodulation. The PCF injects light into the middle hole, enhancing the radiated evanescent field. Analytes injected through the core cause a wavelength shift, measured by peak or dip shift. The proposed sensor has an optimal sensitivity of −7,940 nm/RIU, −8,265 nm/RIU, −9,747 nm/RIU, −9,006 nm/RIU, and −8,994 nm/RIU by peak shift and −8,745 nm/RIU, −10,728 nm/RIU, −8,721 nm/RIU, −10,113 nm/RIU, and −11,150 nm/RIU by dip shift for CRT-(Cervical tissue), BLD-(Blood), ADG-(Adrenal gland), BRT-(Breast) type-1 and type-2 cells, respectively. The PCF sensor presents a shorter sensing length of 550 µm. Results suggest the sensor is effective in detecting malignant neoplastic cells in earlier stages, making it a promising tool for cancer diagnosis and treatment.

A Highly Birefringent Photonic Crystal Fiber with Three Rows of Circular Air Holes

An exceptionally high-performance, high-birefringent photonic crystal fiber (PCF) is meticulously designed. The core design features a unique arrangement in which the central row of circular air holes is substituted by three rows of smaller circular holes. Subsequently, the middle row is adjusted to achieve various rectangular mode field configurations. With the optimized structure parameters, the birefringence of the PCF can reach 3.57 × 10−2 at a wavelength of 1.55 μm. The confinement loss is as low as 8.4 × 10−6 dB/m. The nonlinear coefficient is up to 41 W−1·km−1. The dispersion is relatively flat within the range from 1.3 μm to 1.9 μm. These remarkable characteristics render the proposed PCF a strong candidate for applications in polarization preservation, dispersion compensation, wideband supercontinuum generation, and other related fields.

Highly sensitive sensor for simultaneous underwater measurement of salinity and temperature based on highly birefringent asymmetric photonic crystal fiber

This paper describes a novel compact fiber sensor with high sensitivity for the simultaneous measurement of underwater salinity and temperature by simulation. The structure is based on a highly birefringent, asymmetric, full-circular hole photonic crystal fiber (HB-A-FCH PCF), which achieves the birefringence value of 2.83 × 10-3 at the wavelength of 2.2 µm. In addition, with ethanol-filled specific air holes, the temperature sensitivity of HB-A-FCH PCF is remarkably improved. Therefore, considering the high birefringence property, we simulate a Michelson interferometer-based sensor setup with air holes as fluid microchannels and simultaneously measure salinity and temperature through the spectral responses of the x- and y-polarization state. Theoretical analysis shows the sensor can achieve the salinity and temperature sensitivity up to 5.1472 nm/% and −0.8987 nm/°C in x-polarized fundamental mode, respectively, whereas the salinity and temperature sensitivity up to 4.5386 nm/% and −0.8000 nm/°C in y-polarized fundamental mode, respectively.

Polarization Characteristics of High Birefringence Photonic Crystal Fiber with Ferries-Wheel-Like Porous Core in Terahertz Regime

Polarization Characteristics of High Birefringence Photonic Crystal Fiber with Ferries-Wheel-Like Porous Core in Terahertz Regime

High birefringence and nonlinearity photonic crystal fiber

High birefringence and nonlinearity photonic crystal fiber

High birefringence and nonlinear photonic crystal fiber with two zero-dispersion wavelengths

High birefringence and nonlinear photonic crystal fiber with two zero-dispersion wavelengths

Delineation of profoundly birefringent nonlinear photonic crystal fiber in terahertz frequency regime

Abstract The photonic aspects of semiconducting hexagon-shaped photonic crystal fiber including effective mode area, effective mode index, dispersion, and confinement loss, have already been investigated. The finite element method has been used to compute the maximum distribution of the studied photonic crystal fiber by COMSOL software. The linear modifications from both the effective mode index and an effective mode area have been investigated. Dispersion and confinement loss are examined in terms of air hole ring number and wavelength. For every wavelength, the effective-index model implies that the studied fiber can indeed be single mode. Even though its practical single-mode range inside the opacity aperture of silica appears large, it is eventually confined by a bend-loss edge at both brief & medium wavelengths. Moreover, the reported fiber offers minimal confinement loss of almost 10−8 dB/cm, birefringence 0.0012, and dispersion around 10−11 ps/km nm.

Double U-groove temperature and refractive index photonic crystal fiber sensor based on surface plasmon resonance.

Based on double U-groove photonic crystal fiber (PCF), a surface plasmon resonance sensor with dual parametric detection of temperature and refractive index is proposed. The birefringence of PCF is increased by using germanium ions doped in the core and introducing U-shaped notches on both sides of the D-shaped fiber. The polished surface of the PCF is coated with gold film and PDMS as a temperature sensing channel, and the U-shaped groove is coated with gold film as a refractive index sensing channel. Through the design of the sensor, it is finally possible to achieve independent measurement of the two parameters. The sensor has a maximum wavelength sensitivity of 4715 nm/RIU in the analyte refractive index range of 1.32-1.4, and maximum wavelength sensitivity of 18 nm/°C in the ambient temperature range of -30∘C-50∘C. The proposed sensor has broad application prospects in scenarios such as blood analysis, DNA hybridization analysis, and microenvironmental cell interactions.

Soliton trapping and orthogonal Raman scattering in a birefringent photonic crystal fiber

We report on trapped pulse generation in birefringent photonic crystal fiber. Linearly polarized ultrashort pulses are injected into the fiber in an anomalous dispersion regime. We observed experimentally that a soliton pulse polarized along the fast fiber axis partially transfers its energy to the orthogonal polarization. The generated pulse is amplified through the orthogonal Raman gain. The two polarization components are located at group-velocity-matched wavelengths. The experimental works are in agreement with numerical simulations. The obtained results are important for applications of the light sources using self-frequency shifted solitons that demand high polarization purity.