Cladding Photonic Crystal Fiber Research Articles

Highly sensitive hybrid structured based dodecagonal core with double layer hexagonal cladding photonic crystal fiber for food oil health sensing

Highly sensitive hybrid structured based dodecagonal core with double layer hexagonal cladding photonic crystal fiber for food oil health sensing

Side-polished photonic crystal fiber sensor with ultra-high figure of merit based on Bloch-like surface wave resonance

A Bloch surface wave (BSW) resonance configuration is introduced for biosensing with an ultra-high figure of merit (FOM). The BSW excitation is realized through the evanescent field of the core-guided fundamental mode of a side-polished photonic crystal fiber (PCF). By taking advantage of the air hole periodic microstructure of the PCF cladding, the BSW platform can be achieved with only a single high refractive index dielectric layer on its flat surface. The dielectric layer deposited on the polished surface of the PCF modifies the local effective refractive index, allowing direct manipulation of the BSWs, whereby the resonance wavelength of the surface wave can be adjusted by choosing the material and thickness of this layer. Here, we numerically investigate Bloch-like surface wave (BLSW) resonance conditions around telecom wavelengths for silicon, titanium dioxide, copper monoxide, and aluminum oxide termination layers. The BLSW excitation platform materials have low loss, which results in higher surface field enhancements and narrower resonances, which are advantageous properties for the sensors. The obtained results open new avenues for the application of optical surface waves in biosensing with high FOM. Furthermore, these results show a much higher figure of merit (FOM) than traditional approaches, allowing for increased sensitivity and accuracy.

Performance analysis of slotted rectangular photonic crystal fiber structures in terahertz waveguidance

For an efficient and reliable transmission of data beyond 5G and 6G technologies, proper waveguide structures are needed. We present a rectangular solid-core slotted cladding photonic crystal fiber (PCF) and analyze its signal transmission capability in the terahertz (THz) regime. The proposed PCF performances have been investigated numerically using the finite element method. Various parameters, such as birefringence, core power fraction, effective material loss, effective area, mode-field diameter, beat length, dispersion, confinement loss, etc., have been studied by varying the geometry of the PCFs. The obtained simulation results exhibit dispersion of the order 2 ns / THz / cm, high birefringence of 0.0983, low confinement loss of the order 10 − 19 mm − 1, the effective area of 0.073 mm2, and high core power fraction of 99.8% in 0.2 to 2 THz range. All the parameters have been optimized among six different structures of the proposed PCF. This analysis will be helpful for the researchers to predict the transmission capability of THz waves in a rectangular PCF waveguide, which assures the boost in communication beyond 5G toward 6G evolution.

Simulation and analysis of supercontinuum generation in the waveband up to 25 µm.

The ultra-wideband supercontinuum generation (SCG) in a Te-based chalcogenide (ChG) photonic crystal fiber (PCF) is simulated in the mid-infrared (MIR) waveband. The PCF core and cladding materials are Ge20As20Se15Te45 and Ge20As20Se17Te43, respectively. The supercontinuum (SC) broadening affected by the core diameter and fiber absorption is considered. The selected PCFs at different pumping wavelengths can demonstrate the generation of ultra-wideband MIR supercontinuum according to the simulated results. We consider SC broadening with and without fiber absorption. A SC range from 3 to 25 µm is demonstrated by simulation in a PCF with a core diameter of 8 µm and a pump wavelength of 6 µm considering the fiber absorption. With the increase of the peak power and the pulse width and the decrease of the core diameter, the degree of coherence gradually degraded. To the best of our knowledge, this is the first demonstration of the possibility of SCG up to the waveband of 25 µm in fiber. Our results highlight the potential of a novel Te-based chalcogenide multi-material PCF for SCG. We also provide a way to generate the SCs to longer wavebands than 20 µm in fiber, especially up to the far-infrared waveband.

Simultaneous measurement of magnetic field and temperature based on photonic crystal fiber plasmonic sensor with dual-polarized modes

A photonic crystal fiber (PCF) based on surface plasmon resonance (SPR) sensor with two orthogonally polarized core modes is designed to achieve simultaneous measurement of magnetic field and temperature. According to the sensing principle, four large ring microfluidic detection channels coated with silver-tantalum pentoxide (Ag-Ta2O5) composite films are symmetrically distributed in the PCF cladding, where the upper and lower channels are filled with magnetic fluids (MFs), and the temperature-sensitive material is infiltrated into the left and right channels. The refractive index (RI) of the MFs has strong dependence on the magnetic field and temperature, while the RI of the temperature-sensitive material is merely affected by the temperature. Therefore, the information on the magnetic field and temperature carried by two orthogonally polarized core modes can be separated. The effect of the structure parameters of the proposed sensor on the sensing performance are evaluated through the optical loss spectrum based on finite element method (FEM). The numerical results show that a dual-parameter sensing matrix on simultaneous measurement of the magnetic field and temperature is established, revealing a magnetic field sensitivity of 265 pm/Oe in the range of 20–300 Oe and a temperature sensitivity of − 1410.7 pm/°C in the range 20–80 °C. The designed sensor overcomes the cross-sensitivity problem when the magnetic field and temperature are measured at the same time, which has a potential application in the fields of dual-parameter sensing.

Highly sensitive SPR-based PCF bio sensor for plasma cell detection in human blood for the detection of early stage cancer

This study investigates an extremely sensitive surface plasmon resonance (SPR)-based Photonic crystal fiber (PCF) biosensor to detect blood plasma cell. A blood sample is put into one of the PCF cladding's air holes. This results in a substantial confinement loss which is used to study as the analyte core mode, while the background is used as the silica mode. To induce plasmonic effects, the plasma sample is injected into one of the air holes in the PCF cladding and its outer covering is coated with Indium Tin Oxide (ITO). In the range of 1.3246–1.3634 for the analyte refractive index, this determination of plasma yielded a sensitivity of 6701.03 nm/RIU for x-polarization and 5154.63 nm/RIU for y-polarization. The provided sensor's sensing output is investigated by using Finite Element Method (FEM)-based programme with a detection limit of 0.0097 RIU overall. Using the analyte defect layer with varied refractive indices, we were able to generate a difference in the resonant peak positions. As a result of our simulation results, it is vital to highlight that the suggested sensor exhibits notable sensor performance for both polarization modes, allowing for more frequent light source selection during practical implementation. Our proposed sensor can detect organic chemicals, biochemical analytes, and can also be used extensively in medical diagnostics, according to the findings.

Magnetic Field Sensing Based on Whispering Gallery Mode with Nanostructured Magnetic Fluid-Infiltrated Photonic Crystal Fiber.

A kind of novel and compact magnetic field sensor has been proposed and investigated experimentally. The proposed sensor consists of a tapered single mode fiber coupled with a nanostructured magnetic fluid-infiltrated photonic crystal fiber, which is easy to be fabricated. The response of magnetic fluid to magnetic field is used to measure the intensity of magnetic field via whispering gallery mode. The magnetic field-dependent shift in resonance wavelength is observed. The maximum magnetic field intensity sensitivity is 53 pm/mT. The sensor sensitivity is inversely proportional to the thickness of the photonic crystal fiber cladding.

Plasmon-Enhanced Refractometry Through Cladding Mode Excitation by a Fiber Bragg Grating in Photonic Crystal Fiber

We report on an extrinsic surface plasmon-enhanced refractometer based on cladding mode resonance excitation in a photonic crystal fiber (PCF) equipped with a straight fiber Bragg grating (FBG). First, we show that the lattice pitch and the air hole diameter of the PCF microstructure define the spectral location of the excited cladding mode resonances. Second, we demonstrate that if the PCF parameters are properly selected, those resonances are sensitive to increases in steps of 1 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−4</sup> refractive index units (RIU) of the refractive index value close to that of water. To the best of our knowledge, this is the first time that the sensitivity of PCF cladding mode resonances to refractive index changes in water-based solutions is reported. We achieved experimental values of 40.3 nm/RIU in terms of wavelength sensitivity and −801 dB/RIU in terms of amplitude sensitivity. The performance of our sensor is therefore comparable to that of tilted FBGs in step-index fibers used for water refractometry, which indicates the potential of our PCF sensor for biosensing. In addition, the sensor fabrication does not require any post-processing such as etching or polishing, which allows preserving the integrity of the fiber probe. Finally, the narrow spectrum within which the PCF operates, allows envisaging multi-target detection with a single fiber probe by using cascaded wavelength-multiplexed gratings.

Theoretical Investigation of Mid Infrared Temperature Sensor Based on Sagnac Interferometer Using Chloroform Filled Photonic Crystal Fiber

In this paper, a novel Sagnac Interferometer (SI) based chalcogenide Photonic Crystal Fiber (PCF) temperature sensor is theoretically and numerically analyzed operating in the mid infrared (MIR) region. The PCF cladding air holes are proposed to be filled with a highly temperature sensitive liquid chloroform to enhance the temperature sensitivity. The temperature sensing characteristics of three different infiltration technique is investigated theoretically and compared by Finite Element Method (FEM). Simulation results show that full infiltration performs better than partial infiltration. In the numerical analysis two sensing dips with high linearity is achieved for full infiltration which shows sensitivity of −5.77 nm/°C and 8.49 nm/°C when the temperature increases from 25 to 85 °C for the specific fiber length of 1.532 mm. The R <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> values are 0.957446809 and 0.97680771 for the respective two sensing dips. The proposed highly sensitive sensor has broad detection window which can be applied in fingerprint unlocking, MIR radiation detection in human body, biomedicine applications, and environmental temperature monitoring.

A narrowband dual-polarization filter based on photonic crystal fiber with Au-Ag double-layer films

A narrowband dual-polarization filter based on photonic crystal fiber (PCF) with Au-Ag double-layer films is proposed. The cladding of PCF is composed of three layers of air holes, and Au-Ag double-layer films are coated on two symmetrical air holes to excite surface plasmon resonance (SPR) effect. The special mechanism of the Au-Ag double-layer films takes advantage of the narrower full width at half maximum (FWHM) of silver. On the other hand, gold is used to protect the silver from oxidation and improve the stability of the filter, and can also enhance SPR effect. The simulation results show that the dual-polarization filter with double-layer metal films has higher resonance absorption and better spectra than that with the single-layer metal film. When the thickness of the double-layer metal films is 22.5 nm (the thickness of silver film is 18 nm), the confinement loss of dual-polarization filter at 1430 nm is achieved to 64.08 dB/cm (y-pol core mode) and at 1530 nm is achieved to 37.26 dB/cm (x-pol core mode). The wavelength range of crosstalk (CT) greater than 20 dB and less than −20 dB are 1410–1450 nm and 1510–1550 nm for the device length of 10 mm, respectively. The CT is achieved 555.07 dB and −321.54 dB at the wavelength of 1430 nm and 1530 nm, respectively. These characteristics show that the filter has excellent performance, and will become a suitable candidate for a narrowband polarization filter.

Study on Physical Effects of Optical Fiber Transmission Characteristics Under Nonlinear Optical Effects

Photonic crystal fiber has a special light guiding mechanism and structural tunability, which can produce singular dispersion characteristics and high nonlinearity, which provides new conditions for the research in the field of nonlinear fiber optics. Due to the combined action of a variety of nonlinear optical effects, photonic crystal fibres with different structural parameters and transmission characteristics can produce rich nonlinear spectra under different pump light pulse parameters. We use the photonic crystal fiber cladding section to conduct nonlinear optical experimental research, and obtain the broadband spectral output of soliton wave and dispersive wave. The theoretical analysis and experimentally measured spectra include blue-shifted dispersion waves in the visible light band near 0.5 μm, residual pump light in the 0.82 μm band, soliton waves in the 1.1 μm band, and red-shifted broadband dispersive waves near 2 μm. Corresponding to this, the formation and redshift of solitons can be clearly seen in the time domain, and there is no more oscillation secondary peak in the femtosecond transmission pulse.

Dual-band fiber optical parametric amplification in a structure of highly nonlinear photonic crystal fiber

We investigate fiber optical parametric amplification (FOPA) in a structure of an As2S3 core and TeO2 cladding photonic crystal fiber (PCF). Various amplification features such as wavelength area, parametric gain value, and bandwidth are investigated. In order to design the FOPA system with optimal features, effects of different structural parameters variation on optical features of the PCF and parametric gain subsequently are also investigated numerically based on the finite-difference time domain numerical method. Using 15 cm of this fiber and a continuous wave pump laser of 1.1 W, we attain a gain spectrum of 350 nm with a maximum value of 37 dB around 1550 and 1310 nm, which are favored wavelengths in optical telecommunication systems. In fact, our structure ends in a wideband amplifier in an absolutely compact size, which is optimized exactly for optical telecommunication applications.

Bloch waves at the surface of a single-layer coating D-shaped photonic crystal fiber.

Bloch surface wave (BSW) platforms are particularly interesting for light confinement and surface sensitivity, as an alternative to the metal-based surface plasmon polaritons (SPP). However, most of the reported BSW platforms require depositing a large number of alternating dielectric layers to realize the excitation of the surface waves. In this Letter, we demonstrate an experimentally feasible D-shaped photonic crystal fiber (PCF) platform consisting of only a single dielectric layer on its flat surface, which can sustain Bloch waves at the boundary between the dielectric layer and the PCF cladding. The presence of the dielectric layer modifies the local effective refractive index, enabling a direct manipulation of the BSWs. In addition, the D-shaped structure provides direct contact with the external medium for sensing applications with an ultrahigh sensing figure of merit ($2451\;{{\rm RIU}^{ - 1}}$2451RIU-1) and has the potential to be used over a wide range of analyte refractive indices.

Design of polarization splitter using elliptically dual core – Cladding photonic crystal fiber

Abstract In this work, the polarization splitter using dual-core elliptically cladding photonic crystal fiber is numerically investigated. The design features the polarization inducement with four distinct modes known as even and odd mode in X - polarization and Y - polarization respectively. Coupling length and normalized transmission are calculated. The result reveals that the polarization component is splitted at 1.56 μm. All the numerical studies are applied using the finite element method (FEM).

Highly birefringent photonic crystal fiber with hybrid cladding

Abstract A highly birefringent hybrid cladding photonic crystal fiber (PCF) is proposed in this article. The guiding properties of the proposed PCF are numerically investigated using the finite element method (FEM). This fiber exhibits very high birefringence in the order of 10 - 2 at communication wavelengths. In addition, low confinement loss of 6.1 × 10−3 dB/km, lower negative dispersion of - 274.5 p s / n m / k m and higher nonlinearity of 76.41 W - 1 k m - 1 is achieved at the same wavelengths compared with the exist literature. The proposed simple cladding structure is easy for fabrication. Moreover, effective mode area and nonlinear coefficient are analyzed and optimized. The proposed fiber can prove its applications in sensing, telecommunication and non-linear technologies.

Generation of an ultrabroadband supercontinuum in the mid-infrared region using dispersion-engineered GeAsSe photonic crystal fiber

An ultrabroadband mid-infrared (MIR) region supercontinuum (SC) is demonstrated numerically through dispersion-engineered traditional chalcogenide (ChG) photonic crystal fiber (PCF). By varying structural parameters pitch (hole to hole spacing) and air-hole diameter to pitch ratio, a number of 10-mm-long hexagonal PCFs made employing GeAsSe ChG glass as a core and air-holes of hexagonal lattice running through their lengths as a cladding are optimized to predict an efficient mid-infrared region SC spectral emission by pumping them using a tunable pump source between 2.9 and 3.3 µm. Simulations are carried out using an ultrashort pump pulse of 100-fs duration with a low pulse peak powers of between 3 and 4 kW into the optimized designs. It is found through numerical analysis that efficient SC spectral broadening with flattened output can be obtained by increasing the PCF pitch rather than increasing the PCF cladding containing air-hole diameter although a larger nonlinear coefficient could be obtained through increasing air-hole diameter of an optimized design. Simulation results show that the SC spectra can be broadened up to 12.2 µm for a certain design with a peak power of 3 kW. Using a peak power of 4 kW, it is possible to obtain SC spectral broadening beyond 14 µm with an optimized design spanning the wavelength range from 1.8 to 14 µm which covers the electromagnetic spectrum required for MIR molecular fingerprint region applications such as sensing and biological imaging.

High-order orbital angular momentum mode generator based on twisted photonic crystal fiber.

High-order orbital angular momentum (OAM) modes, namely, OAM+5 and OAM+6, were generated and demonstrated experimentally by twisting a solid-core hexagonal photonic crystal fiber (PCF) during hydrogen-oxygen flame heating. Leaky orbital resonances in the cladding depend strongly on the twist rate and length of the helical PCF. Moreover, the generated high-order OAM mode could be a polarized mode. The secret of the successful observation of high-order modes is that leaky orbital resonances in the twisted PCF cladding have a high coupling efficiency of more than -20 dB.

Mach-Zehnder interferometric magnetic field sensor based on a photonic crystal fiber and magnetic fluid.

A Mach-Zehnder interferometric magnetic field sensor based on a photonic crystal fiber (PCF) and magnetic fluid (MF) was designed and experimentally demonstrated. The sensing probe consists of a single-mode-(SM)-multimode-PCF-SM fiber structure through arc fusion splicing. It was then laser engrave notched with the femtosecond laser so that the PCF cladding was selectively infilled MF. A well-defined interference pattern was obtained on account of the tunable refractive index of the MF infilled PCF cladding. The transmission spectra of the proposed sensor under different magnetic field intensities have been measured and theoretically analyzed. The results show that the sensitivity of the proposed sensor can reach -0.13 dB/mT and 0.07334nm/mT in the magnetic field intensity from 1mT to 20mT and 2mT to 20mT, respectively.

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

High-sensitivity photonic crystal fiber long-period grating methane sensor with cryptophane-A-6Me absorbed on a PAA-CNTs/PAH nanofilm.

A high-sensitivity photonic crystal fiber long-period grating (PCF-LPG) methane sensor with cryptophane-A-6Me absorbed on a poly(acrylic acid)-carbon nanotubes/ polypropylene amine hydrochloride (PAA-CNTs/PAH) nanofilm was investigated. The sensing film was coated onto the internal surface of a photonic crystal fiber cladding air holes by an electrostatic self-assembly technique. Based on a finite element method and the coupled local-mode theory, the effects of the sensing film's refractive index (RI) and thickness on the resonant wavelength were theoretically and numerically analyzed. When the sensing film RI decreases from 1.55 to 1.53, and the thickness increases from 100 nm to 200 nm, the resonant wavelength has a blue shift. A higher RI sensitivity with 1.075 × 103 nm RIU-1 is observed for the film thickness of 200 nm. The PCF-LPG methane sensor was fabricated by a pressurized injection method. The sensing experimental result shows that the resonant wavelength of the transmission spectra has a blue shift when the methane concentration increases from 0.0% to 3.5% by volume. The sensor has a good sensitivity of 1.078 nm%-1 and a low detection limit of 0.18% for a film thickness of 210 nm.