Lattice Photonic Crystal Fiber Research Articles

Surface plasmon resonance biosensor based on hexagonal lattice dual-core photonic crystal fiber.

In this paper, the guiding properties and sensor performance are numerically investigated for a dual-core hexagonal lattice photonic crystal fiber sensor based on surface plasmon resonance (SPR). Gold is used as the active plasmonic material in order to create resonance, and it is placed outside the fiber structure to facilitate the fabrication process. The finite-element method is used to numerically investigate the characteristics of the sensor. By means of wavelength and amplitude interrogation methods, it is found that the proposed sensor shows maximum wavelength sensitivity of 16,000 nm/RIU with $6.25 \times {10^{ - 6}}\,\,{\rm RIU}$6.25×10-6RIU resolution and amplitude sensitivity of $2255\,\,{{\rm RIU}^{ - 1}}$2255RIU-1 with $4.40 \times {10^{ - 6}}\,\,{\rm RIU}$4.40×10-6RIU resolution. The proposed SPR sensor can detect the analyte refractive index ranging from 1.33 to 1.40. This work also includes an investigation of the effect of changing the gold layer thickness, air-hole diameter, and analyte layer on the sensor performance from the optimized design. The proposed sensor could be employed to detect biological and biochemical analytes because of its simple design and promising results.

A squeezed photonic crystal fiber for residual dispersion compensation with high birefringence over S+C+L+U wavelength bands

A squeezed triangular lattice photonic crystal fiber (PCF) composed of elliptical air holes is presented in this paper. Full vector finite element method (FEM) is used to investigate the guiding property. By adjusting the size of air holes in cladding, the fiber offers a flat negative dispersion of -1343.46 ± 6.74 ps/(nm.km) over the wavelength bands of S+C+L+U. The birefringence can be on the order of 10−2 which reaches up to 3.72×10−2 at the wavelength of 1.55μm. The proposed PCF may show some important applications in residual dispersion compensation and polarization maintaining fibers.

Mid-infrared broadband ultraflat-top supercontinuum generation in dispersion engineered Ge-Sb-Se chalcogenide photonic crystal fiber

In this paper, we numerically demonstrate broadband, ultraflat-top and highly coherent mid-infrared Supercontinuum (SC) generation in an all-normal dispersion (ANDi) Ge15Sb15Se70 chalcogenide Circular Lattice Photonic Crystal Fiber (CL-PCF). The propagation properties of the fundamental mode are computed with the Finite Difference Method (FDM). Numerical results show that ANDi regime is obtained over the entire mid-infrared wavelength range with a cladding pitch and air holes diameter of Λ=2 μm and d=0.8 μm, respectively. Besides, the proposed CL-PCF exhibits small effective mode area and high Kerr nonlinearity up to 1.96 W−1 m−1 at 3 μm. Ultrashort pulse propagation inside the CL-PCF core is modelled by using the Generalized Non-Linear Schrodinger Equation (GNLSE). Simulation results show that by pumping at 3 μm laser pulses with a total energy of 0.6 nJ and duration of 50 fs, into 10 mm long of the CL-PCF, generates an ultrabroadband and highly coherent SC spanning the wavelength region from 1.86 μm to 5.35 μm within less than 3 dB spectral dynamics. By increasing the initial pulse energy to attain 1 nJ, the generated SC bandwidth increases too and reaches 4.53 μm in the spectral range extending from 1.67 μm to 6.2 μm at 4 dB spectral level. Moreover, the proposed CL-PCF based SC source is found promising for application in Optical Coherence Tomography (OCT) with an axial resolution of 0.87 μm, achieved when pumping 1 nJ energy and 50 fs duration optical pulses.

A Bimetallic-Coated, Low Propagation Loss, Photonic Crystal Fiber Based Plasmonic Refractive Index Sensor

In this paper, a low-loss, spiral lattice photonic crystal fiber (PCF)-based plasmonic biosensor is proposed for its application in detecting various biomolecules (i.e., sugar, protein, DNA, and mRNA) and biochemicals (i.e., serum and urine). Plasmonic material gold (Au) is employed externally to efficiently generate surface plasmon resonance (SPR) in the outer surface of the PCF. A thin layer of titanium oxide (TiO2) is also introduced, which assists in adhering the Au layer to the silica fiber. The sensing performance is investigated using a mode solver based on the finite element method (FEM). Simulation results show a maximum wavelength sensitivity of 23,000 nm/RIU for a bio-samples refractive index (RI) detection range of 1.32–1.40. This sensor also exhibits a very low confinement loss of 0.22 and 2.87 dB/cm for the analyte at 1.32 and 1.40 RI, respectively. Because of the ultra-low propagation loss, the proposed sensor can be fabricated within several centimeters, which reduces the complexity related to splicing, and so on.

Asymmetrical photonic crystal fiber based plasmonic sensor using the lower birefringence peak method

An asymmetrical configuration of hexagonal lattice photonic crystal fiber (PCF) based surface plasmon resonance (SPR) refractive index sensor is proposed. Instead of the typical confinement loss method, the lower birefringence peak method is considered to explore the sensing performance. The asymmetry in the core region induces birefringence that enhances the coupling efficiency between the core and surface plasmon polariton (SPP) mode. To form the strong SPR effect, both the gold layer and analyte layer are deposited on the external surface of the PCF. The proposed birefringent sensor exhibits the maximum wavelength sensitivity of 22,000 nm/RIU within broad analyte refractive index (RI) from 1.33 to 1.42. The sensing characteristics are carried out with the variation of several PCF structural parameters. Owing to enhanced sensitivity, the proposed sensor can be a potential candidate for biological and biomolecular analyte detection.

Simultaneously Achieving a Large Negative Dispersion and a High Birefringence Over Er and Tm Dual Gain Bands in a Square Lattice Photonic Crystal Fiber

Simultaneously Achieving a Large Negative Dispersion and a High Birefringence Over Er and Tm Dual Gain Bands in a Square Lattice Photonic Crystal Fiber

Polarization Converter Based on Square Lattice Photonic Crystal Fiber with Double-Hole Units

In this study, a novel polarization converter (PC) based on square lattice photonic crystal fiber (PCF) is proposed and analyzed. For each square unit in the cladding, two identical circular air holes are arranged symmetrically along the y = x axis. With the simple configuration structure, numerical simulations using the FDTD analysis demonstrate that the PC has a strong polarization conversion efficiency (PCE) of 99.4% with a device length of 53 μ m, and the extinction ratio is −21.8 dB. Considering the current PCF fabrication technology, the structural tolerances of circular hole size and hole position have been discussed in detail. Moreover, it is expected that over the 1.2∼1.7 μ m wavelength range, the PCE can be designed to be better than 99% and the corresponding extinction ratio is better than − 20 dB .

Coherent supercontinuum generation in tellurite glass regular lattice photonic crystal fibers

We report on designing, fabrication and experimental characterization of highly nonlinear, tellurite glass photonic crystal fibers with engineered normal dispersion characteristics for coherent supercontinuum generation. Effectively single mode, air-hole lattice fibers, with measured, all-normal dispersion profiles as flat as -10 to -50 ps/mn/km over 1500-2400 nm wavelengths are developed and investigated. Supercontinuum spectra are measured for these fibers, with a spectral width covering 1100-2600 nm wavelengths under pumping with a robust, fixed-wavelength erbium fiber-based femtosecond laser, delivering 90 fs pulses, centered at 1560 nm with peak power below 40 kW. To the best of our knowledge, this is the first engineered microstructured fiber, which due to its high nonlinearity, enables a self-phase modulation and optical wave breaking-based supercontinuum pumped with a turn-key, 40 kW femtosecond laser at spectral widths obtainable with previous all-normal dispersion fiber designs only under pumping with systems delivering peak power in the MW range.

Corrections to “Simultaneously Achieving a Large Negative Dispersion and a High Birefringence Over Er and Tm Dual Gain Bands in a Square Lattice Photonic Crystal Fiber”

We proposed a novel photonic crystal fiber composed of a double-cladding square lattice that could be used in dual-band, Er and Tm optical gain bands, simultaneously supporting a large negative dispersion and a high birefringence. We theoretically investigated the light guiding property through the proposed photonic crystal fiber by using a vectorial finite-element method with a perfectly matched layer. By optimizing the structural parameters, we obtained an ultra-large negative dispersion of −20,186 ps/(nm·km) and a very high birefringence of 9.27 × 10−3 at the wavelength of 1.55 μ m in the Er gain band and a very large negative dispersion of −8,067 ps/(nm·km) and a high birefringence of 1.0 × 10−3 at the wavelength of 1.87 μ m in the Tm band. We further discussed the roles of waveguide parameters on the chromatic dispersion, its slope, and the birefringence of the fiber as well as the mode field diameter. The proposed fiber could be directly applied for dual-band dispersion and polarization control in fiber laser cavities as well as optical communications and sensors in the dual bands.

Wideband Dispersion Compensation in Hexagonal Lattice Photonic Crystal Fiber

Wideband Dispersion Compensation in Hexagonal Lattice Photonic Crystal Fiber

Rectangular lattice photonic crystal fiber with simultaneous polarization filtering at communication wavelengths of 1310 nm and 1550 nm

In this study, we developed a tunable photonic crystal fiber (PCF) polarized filter with a gold coating and liquid filling, which was investigated using the full-vector finite-element method. The gold that selectively filled the cladding air holes acted as a defect mode. When light was transmitted into the core, the energy was transferred from the core mode to the defect mode at a given wavelength and a resonance peak was obtained. Numerical results showed that the proposed PCF could be implemented simultaneously for polarization filtering in the communication windows of 1.31 and 1.55 μm. The confinement losses for the y-polarized mode were 251.5 dB/cm for 1.31 μm and 375.3 dB/cm for 1.55 μm. When the fiber length was 90 μm, the corresponding bandwidths were just less than 20 and 70 nm for 1.31 and 1.55 μm, respectively. The bandwidths are the narrowest obtained and they are conducive to applications in integrated systems. We also studied the effects of structural parameters on the resonance performance. The optical fiber structure could be optimized further to obtain better results.

Design and analysis of a Zeonex based diamond-shaped core kagome lattice photonic crystal fiber for T-ray wave transmission

Abstract A new kind of Zeonex based single mode photonic crystal fiber (PCF) has been designed and analysed for low loss terahertz wave transmission. The novel twist is introduced in a kagome lattice PCF by placing a diamond shaped core. Various geometrical parameters including core diameter, pitch distance, porosity, strut length and strut width are adjusted to optimize the PCF. Using Finite Element Method (FEM) simulation results show a low effective material loss (EML) of 0.04 cm−1 that is 80% lower than bulk material absorption loss of Zeonex, low confinement loss of 0.0001 cm−1 at 1 THz frequency and near zero flattened dispersion variation of 0.98 ± 0.09 ps/THz/cm with 1 THz transmission bandwidth. Owing to the above remarkable properties, the proposed waveguide can be a suitable candidate for improved transmission of terahertz waves.

All-normal dispersion supercontinuum generation in photonic crystal fibers with large hollow cores infiltrated with toluene

An all-normal dispersion supercontinuum generation in the range of 950 ÷ 1100 nm in photonic crystal fiber with core infiltrated with toluene is reported. The regular lattice hollow core photonic crystal fiber with a large core of 12 μm was designed and developed. The photonic crystal fiber core was selectively filled with toluene. The investigated fiber has normal dispersion in the wavelength range of 0.5 ÷ 2μm, while the absolute value of dispersion varies from 150 to 5 ps/nm/km in the range of 1 ÷ 2µm wavelength. The fiber nonlinear coefficient is 130 W−1km−1 as a result of the trade-off of high nonlinearity of toluene and a large mode area of the fundamental mode. The large mode area is required for the efficient delivery of high power pulses from large mode area input fiber in an all fiber system. As a pump source, a standard subpicosecond fiber laser emitting at 1030 nm with 10nJ pulse energy was used.

Mid-infrared dual-rhombic air hole Ge20Sb15Se65 chalcogenide photonic crystal fiber with high birefringence and high nonlinearity

We propose a mid-infrared dual-rhombic air hole hexagonal lattice photonic crystal fiber with high birefringence and large nonlinearity based on Ge20Sb15Se65 chalcogenide glass. The properties of birefringence, dispersion, nonlinearity, and confinement loss were investigated in the 3 µm~5 µm mid-infrared range by using the Finite Difference Time Domain (FDTD) method with perfectly matched layer (PML) absorption boundary conditions. The results indicate that for the optimized structural parameters of Λ= 2.0 µm, D= 1.932 µm, d= 0.8 µm, and H= 0.8 µm, an ultrahigh birefringence of 0.041, a very low confinement loss of 0.0013 dB/km (for x-polarization modes) and 0.0342 dB/km (for y-polarization modes), and the maximum nonlinearity coefficient of 4375 w−1km−1 (for x-polarization modes) and 3960 w−1km−1 (for y-polarization modes) were achieved, respectively. The proposed PCF has a lower confinement loss and higher birefringence than an elliptical-hole PCF with the same air-filling fraction. Thus, it will be an excellent candidate for mid-infrared optical fiber sensing, precision optical instruments and nonlinear optics.

Midinfrared high birefringence Ge20Sb15Se65-based photonic crystal fiber with large nonlinearity using dual-rhombic air hole

A midinfrared high birefringence Ge20Sb15Se65-based hexagonal lattice photonic crystal fiber (PCF) with central defect core and dual-rhombic air holes cladding is proposed. The finite difference time-domain method with perfectly matched layer absorption boundary conditions are used to numerically analyze the guided modes of the designed PCF. The properties of this PCF including the birefringence, beat length, dispersion, and nonlinearity are investigated in the 3 to 5 μm midinfrared range. The results show that for the optimized structure parameters of Λ = 2 μm, D = 1.7 μm, H = 1.76, and d = 0.4 μm, the highest birefringence of 0.1513 and beat length of 33.04 μm are obtained. The maximum nonlinearity coefficients of 3726 and 2585 w − 1 km − 1 for x- and y-polarization modes are achieved. The distinctive dispersion is acquired, which is all-normal for x-polarization mode while has single zero dispersion points at 3.96 μm for y-polarization mode. The designed PCF will have broad application in midinfrared optical fiber sensing, nonlinear optics, and precision optical instruments.

Gold-coated photonic crystal fiber biosensor based on surface plasmon resonance: Design and analysis

The particularly sensitive circular lattice Photonic Crystal Fiber (PCF) based Surface Plasmon Resonance (SPR) sensor is proposed to gain high sensitivity for the detection of unknown analytes. In this model, two-layer PCF based on the SPR has been designed. A plasmonic chemically inactive material gold (Au) with thickness 35 nm is used to the outside of the PCF structure which exhibits negative real permittivity. A circular perfectly match layer (PML) outside the structure is applied to evaluate the performance of the sensor. The raised design has consisted of symmetric air-hole. Three small air-holes are used in second layer and center which help us to produce more evanescent field. Using the wavelength interrogation method the proposed model shows the maximum wavelength sensitivity of 9000 nm/RIU (Refractive Index Unit) and using the amplitude interrogation method it shows the maximum amplitude sensitivity of 318 RIU−1 with maximum sensor resolution 1.11 × 10−5 in the sensing range among analyte 1.34–1.37. Here the proposed model is investigated how phase matching points are varied with changing parameters as like diameter, PML, thickness of gold (Au), sensing layer and pitch. The obtained result reveals that the proposed model may be used in biochemical and biological analyte detection to find out the important application.

Mid-infrared high birefringence As2Se3-based PCF with large nonlinearity and distinctive dispersion by using asymmetric elliptical air hole cladding

A novel high birefringence As2Se3-based hexagonal lattice photonic crystal fiber (PCF) is proposed. In the structure, a central defect core and three kinds of elliptical air holes with different major axes length and ellipticity are introduced in the cladding. The finite difference time domain (FDTD) method with perfectly matched layer (PML) absorption boundary conditions are used to simulate the guided modes of the designed PCF. The properties of this PCF are investigated in detail including the birefringence, beat length, dispersion, nonlinearity and polarization mode dispersion in the 2–5 [Formula: see text] mid-infrared range. The results show that for the optimized structure parameters of [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], the high birefringence of 0.1192 and beat length of 41.93 [Formula: see text] are obtained. The maximum nonlinearity coefficient of 10,050 w[Formula: see text]km[Formula: see text] and 15,200 w[Formula: see text]km[Formula: see text] for x- and y-polarization modes are achieved. The distinctive dispersion is analyzed, which is all-normal in x-polarization direction while it has two zero dispersion points at 3.18 [Formula: see text] and 3.65 [Formula: see text] in y-polarization direction. The designed PCF with high birefringence, large nonlinearity and distinctive dispersion will be beneficial for mid-infrared fiber sensing, mid-infrared spectroscopy and nonlinear optics applications.

Hollow-core silver coated photonic crystal fiber plasmonic sensor

We propose a simple hollow-core circular lattice photonic crystal fiber (PCF) based surface plasmon resonance (SPR) refractive index sensor. The sensing performance is investigated by using the finite element method (FEM). Silver is used as the plasmonic material for this design, which is placed on the outer surface of the PCF to facilitate the fabrication. The proposed sensor shows a maximum wavelength sensitivity of 4200 nm/RIU with a sensor resolution of 2.38 × 10−5 RIU. Besides, a maximum amplitude sensitivity of 300 RIU−1 and a resolution of 3.33 × 10−5 RIU is reported for an analyte refractive index of 1.37. Moreover, the effect of varying structural parameters on the sensing performance such as pitch, air hole diameter and silver layer thickness are also discussed thoroughly. Sensitivity analysis of the proposed sensor is performed in order to investigate the impact on loss depth and amplitude sensitivity. Thanks to high sensitivity and linearity characteristics, the proposed sensor can be potentially employed in practical bio-sensing and chemical sensing applications.

A Novel Tube Lattice Slotted Core Highly Birefringent Photonic Crystal Fiber for THz Application

A hexagonal slotted porous core tube lattice cladding photonic crystal fiber (SPC-TLC-PCF) is suggested to simultaneously achieve a very high birefringence and low transmission loss. At the operating frequency of 1 THz the pr... | Find, read and cite all the research you need on Tech Science Press

Calculation of effective mode field area of photonic crystal fiber with digital image processing algorithm

Photonic crystal fiber as a new type of optical fiber has been extensively applied because of its unique properties. The effective mode area of optical fiber is an important parameter, which has a great influence on the performance of optical fiber. In this study, digital image processing algorithm was used for preprocessing to improve the accuracy of calculation of mode field area. Then the effective mode field area of optical fiber was calculated using Matlab based Gauss fitting method. Take single-mode fiber G.652 as an example, the effective mode field area was calculated using the traditional algorithm and digital image processing algorithm respectively. It was found that the results obtained using digital image processing algorithm were within the allowed error range, suggesting the effectiveness of the algorithm. Then the calculation of the effective mode area of the triangular lattice photonic crystal fiber further verified the reliability of the algorithm.