Average Wavelength Sensitivity Research Articles

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.

Simulation analysis of a photonic crystal fiber refractive index sensor based on a double-layer film structure and surface plasmon resonance technology

A photonic crystal fiber surface plasmon resonance sensor based on a double-layer membrane structure is designed and analyzed. In the simple sensing structure with only one air hole size, TiO2 and Au layers with specific thicknesses are sequentially coated on the optical fiber to form a double-layer structure. The sensing characteristics of the double-layer membrane structure are studied by the finite element method. Compared to the single-layer membrane structure, the double-layer membrane sensor has significant sensing properties such as a better wavelength sensitivity and a smaller full width at half maximum in the loss spectrum. In the refractive index range between 1.37 and 1.43, the maximum wavelength sensitivity and average wavelength sensitivity of the sensor are 19,900 nm/RIU and 7417 nm/RIU, respectively, and the resolution can be up to 5.03×10−6RIU. The proposed photonic crystal fiber optic sensor achieves high performance with a simpler sensing structure than previous photonic crystal fiber optic sensors, and eliminates the step of polishing, which will greatly reduce the difficulty of actual fabrication and the error due to uneven polishing. The results show that the photonic crystal fiber optic sensor with a double-layer membrane structure has excellent performance. Due to its high sensitivity and resolution, it has great potential for applications in environmental monitoring, biosensing and chemical sensing.

Highly sensitive surface plasmon resonance sensor based on the anti-resonant fiber with six nested tubes

On the heels of the continuous development of optical fiber sensing technology, optical fiber sensors based on surface plasmon resonance (SPR) have attracted widespread attention. Herein, an SPR sensor based on the six nested anti-resonant fiber (ARF) is designed and analyzed by the finite element method (FEM). All the structural parameters are optimized to achieve high-sensitivity liquid refractive index detection. Filling the anti-resonant tube with plasmonic materials to excite SPR can further reduce the manufacturing complexity. The optimal ARF-SPR sensor has excellent characteristics, including an average wavelength sensitivity of 42,000 nm/RIU, maximum sensor length of 0.08 cm, and resolution of 1.61×10−6RIU. The ARF-SPR sensor has great potential in chemical analysis, biomedicine, and other fields.

Ultra-high sensitivity D-type photonic crystal fiber sensor deposited with MoO2 nanofilm

Fiber optic sensing technology has extensive applications in many fields and demands high sensitivity and cost-effectiveness for sensors. In this study, we propose an ultra-high sensitivity D-type photonic crystal fiber sensor based on MoO2 nano-film coating to meet this requirement. Firstly, MoO2 is selected as the plasmonic excitation material. Compared to expensive metals such as Au and Ag, MoO2 has the characteristics of low cost and charge carrier density, which is suitable for use in optical fiber sensing modules. The sensitivity of the sensor to the external environment can be increased by coating the surface of the optical fiber with MoO2 nano-film. Then, we use the finite element method to evaluate the performance of the sensor. Numerical simulation results show that the average wavelength sensitivity of the sensor in the x-polarization direction is as high as 24000 nm/RIU when analyzing substances with refractive indices ranging from 1.38 to 1.43. This means that the sensor has a very sensitive response to refractive index changes and can be widely applied to sensing needs in different fields. Overall, the D-type photonic crystal fiber sensor based on MoO2 nanofilm coating has enormous potential for applications. This sensor can achieve high-sensitivity detection within a specified range of refractive indices, providing new ideas and methods for research and applications in the field of fiber sensing.

Surface plasmon resonance methane sensor based on the D-type photonic quasi-crystal fiber with double-layer films

A high-sensitivity photonic quasi-crystal fiber surface plasmon resonance (PQF-SPR) methane sensor is designed and analyzed. The six-fold Penrose PQF has a D-type structure with two grooves on which TiO2 and Au films are deposited, and methane-sensitive film containing cryptophane-E is coated on the surface of the D-type structure. The characteristics of the sensor are analyzed by the finite element method and the influence of different coating materials (Au-TiO2, Au-MgF2, Au-ITO) on the sensitivity and FOM of the sensor is analyzed and compared. The results show that the PCF-SPR sensor with the dual Au-TiO2 film has better sensing properties. The maximum wavelength sensitivity and average wavelength sensitivity reach 40 nm/% and 34.74 nm/% in the methane concentration range of 0–3.5 % respectively. These properties are significantly better than those of similar sensors reported recently, and the sensor thus has large potential in the development of high-sensitivity and miniaturized methane sensors.

Dual-function plasmonic device on photonic crystal fiber for near to mid-infrared regions

Broadband multifunction optical devices can play an important role in the field of integrated photonics but achieving high tunability and versatility on a fabricated device by implementing external control or structural modification is still challenging. In this article, what we believe to be a new dual-function optical device based on photonic crystal fiber, having an ultra-broad bandwidth that partially covers near-infrared (IR) to mid-IR regions, is proposed and analyzed. This device is designed on a fabrication friendly geometry such a way that it can be used as a polarization filter as well as refractive index sensor without any external tuning or structural modification. In this case, plasmonic material plays a crucial role for achieving simultaneous operation of the device both in communication and sensing applications. Our proposed device, with a fiber length of 100 µm, can effectively suppress the y-polarized light within the wavelength range of 1.29 µm to 1.60 µm, while the x-polarized light is maintained properly in the core, and vice-versa for the region of 1.69 µm to 4.39 µm. The maximum confinement losses of 840.8 dB/cm, 1013.2 dB/cm, 659.65 dB/cm, and 792.68 dB/cm are obtained at wavelengths of 1.37 µm, 1.56 µm, 1.72 µm, and 2.65 µm, respectively. By maintaining a crosstalk level of better than 20 dB, this device achieves broad bandwidths of 310 nm over the 1.29 µm to 1.60 µm wavelength range and 2700 nm over the 1.69 µm to 4.39 µm wavelength range. In addition to the filtering performance, our device possesses sensing capabilities, which is also well discussed as an example of refractive index sensor. Considering the analyte refractive index of 1.10-1.40, this device shows an average wavelength sensitivity of 1000 nm/RIU. Therefore, the above exceptional characteristics of our proposed device make it suitable for both optical communication and sensing systems.

High Sensitivity and Wide Range Refractive Index Sensor Based on Surface Plasmon Resonance Photonic Crystal Fiber.

In order to detect the refractive index (RI) of high refractive index materials such as trichlorobenzene and aniline in the near-infrared and mid-infrared spectra and expand the detection range of the refractive index, a surface plasmon resonance (SPR) photonic crystal fiber (PCF) sensor based on an elliptical sensing channel is proposed for high refractive index detection. The fiber core and the analyte channel are surrounded by two types of air holes with different sizes. When the surface plasmon resonance effect appears at the interface between the fiber core and the elliptical sensing layer, obvious resonance peaks appear in the near-infrared and mid-infrared bands. The full vector finite element method (FEM) is used to study the sensing characteristics of the sensor and the influence of structural parameters on the resonance peak. The results demonstrate that the sensor achieves detection in the refractive index range of 1.41-1.58, in the wavelength range of 1600-3200 nm. The average wavelength sensitivity is 9217.22 nm/RIU, and the refractive index resolution is 10.85 × 10-6 RIU. The proposed sensor realizes high refractive index detection in the near-infrared and mid-infrared bands, and obtains an ultra-wide detection range and higher sensitivity. The sensor has broad application prospects in chemical detection, biomedical sensing and other fields, and provides a theoretical reference for the design of a photonic crystal fiber surface plasmon resonance sensor.

A Dual-Core Surface Plasmon Resonance-Based Photonic Crystal Fiber Sensor for Simultaneously Measuring the Refractive Index and Temperature

In this correspondence, a new photonic crystal fiber biosensor structure on the basis of surface plasmon resonance is proposed for the measurement of the refractive index (RI) and TSM temperature simultaneously. In this design, the central and external surface of the biosensor structure are coated with thin gold film. A hole adjacent to the inner gold film is filled with temperature-sensitive material (TSM). With the implementation of internal and external gold coatings along with TSM, the biosensor achieves the measurement of the RI and temperature with two disjoint wavelength coverage. Numerical simulations and calculation results illustrate that the average wavelength sensitivity of the biosensor structure, respectively, achieves 7080 nm/RIU and 3.36 nm/°C with RI coverage from 1.36 to 1.41 and temperature coverage from 0 to 60 °C. Moreover, benefiting from realization of different wavelength regions in RI and temperature sensing, it is believed that the proposed biosensor structure for the measurement of the RI and temperature will have range applications in the fields of medical diagnostics and environmental assessments.

D-Shaped photonic crystal fiber with graphene coating for terahertz polarization filtering and sensing applications

A D-shaped photonic crystal fiber with graphene coating on the polished flat surface is designed. Graphene is used as the plasmonic material and surface plasmon resonance (SPR) effect is obtained at the sub-terahertz frequency. Tunable loss spectra, polarization filtering and sensing properties are studied by using the finite element method. Tuning sensitivity of the SPR frequency is 595 GHz/eV. Bandwidth of 23.46 GHz centered at 0.48THz with crosstalk above 20 dB can be obtained when fiber length is 0.5 cm. The average wavelength sensitivity of 305.5 μm/RIU and the maximum amplitude sensitivity of 30.85RIU−1 are obtained for analyses with refractive index in the range of 1.3 to 1.4. Refractive index resolution of the order of 10−4 is predicted. The designed fiber can be used as terahertz polarization filter or biosensor.

High-sensitivity photonic crystal fiber methane sensor with a ring core based on surface plasmon resonance and orbital angular momentum theory

ObjectiveWith the advent of optical fiber sensing technology, photonic crystal fiber (PCF) sensors based on surface plasmon resonance (SPR) have become a research hotspot. Herein, a PCF-SPR methane sensor with a ring-core structure is designed based on the orbital angular momentum (OAM) theory. To our best knowledge, this type of sensor has not been reported yet. MethodsThrough the finite element method, the PCF structure is designed and the appropriate filling material is selected. ResultsThe sensor consists of a three-layer clad air hole and an extra-large central gas channel, forming a ring core for beam transmission. By adding high refractive index material Amethyst and methane sensitive material to the central gas channel, the mode field is improved and the methane concentration is detected efficiently. Numerical results show that the sensor can stably transmit OAM modes and excite SPR with the OAM2,1 mode, namely the HE3,1 eigenmode. With the help of methane sensitive film, changes in methane concentration can greatly affect the refractive index distribution in PCF and alter the excitation characteristics of SPR. In the methane concentration range of 0–3.5 %, the resonance wavelength shifts from 4.52 µm to 4.58 µm. The average wavelength sensitivity reaches 17.07 nm/%, and the corresponding detection limit is 117 ppm. The results reveal that the designed PCF-SPR methane concentration sensor has excellent performance, which can stably transmit OAM mode while achieving SPR effect. It has great innovation and commercial potential in the petroleum, biomedical, chemical, and other industry.

D-shaped photonic crystal fiber sensor based on the surface plasmon resonance effect for refractive index detection.

In this paper, a photonic crystal fiber (PCF) sensor based on the surface plasmon resonance (SPR) effect for refractive index (RI) detection is proposed. We design a D-shaped polished PCF structure consisting of air holes arranged in a hexagonal lattice. The silver film is coated on the middle channel of the polished surface of the PCF. The finite element method is used to analyze the propagation characteristics of the proposed D-shaped SPR-PCF sensor. Simulation results show that the proposed D-shaped SPR-PCF sensor has a maximum wavelength sensitivity of 30,000nm/RIU, an average wavelength sensitivity of 6785.71nm/RIU, and a maximum resolution of 3.33×10-6 R I U in the RI range of 1.22-1.36. Owing to the high wavelength sensitivity in the considered RI range, the proposed D-shaped SPR-PCF sensor is suitable for applications in water contamination detection, liquid concentration measurement, food safety monitoring, etc.

High Performance Dual-Core D-Shaped PCF Refractive Index Sensor Coated with Gold Grating

In this study, a dual−core D-shaped photonic crystal fiber (PCF) surface plasmon resonance sensor coated with gold grating is designed and analyzed using the finite-element method (FEM). The surface plasmon resonance (SPR) effect between the fiber core modes and surface plasmon polariton (Spp) modes is used to measure the analyte refractive index. The effects of the PCF structure parameters (polishing depths, large holes, and small holes) and grating parameters (grating heights, grating periods, and grating duty) are discussed, and a two-feature interrogation method that combines wavelength and intensity interrogations is introduced to enhance the resolution. The results show that the grating and dual-core play important roles in enhancing the sensor properties. The proposed sensor achieves an average wavelength sensitivity of 994.5 nm/RIU when the analyte refractive index increases from 1.33 to 1.37. Furthermore, a maximum amplitude sensitivity of 181.049 RIU−1 is obtained. The two-feature interrogation is determined to have a resolution of 2.03 × 10−6 RIU, which is better than the wavelength and amplitude interrogations. The proposed sensor has a good sensing performance and is highly suitable for practical applications.

Fiber SPR micro displacement sensor based on heterocore structure of graded index multimode fiber

Based on the self-focusing characteristics of graded index multimode fiber, a fiber SPR micro displacement sensor can be constructed, which has two bottleneck problems of difficult to fabricate and the small displacement detection range. In this paper, we proposed and constructed a new heterocore structure of graded multimode fiber-single-mode fiber-graded multimode fiber to realize the micro displacement sensing, which has stable performance and simple fabrication. By increasing the core diameter of modulation graded multimode fiber and displacement fiber, the displacement detection range of probe was increased. The simulating and testing results indicate that the SPR micro displacement sensor based on the graded multimode heterogeneous core structure can well realize the two-parameter sensing of micro displacement, and its average wavelength and light intensity sensitivity can reach 1.23 nm/μm, and 0.00576 a.u./μm respectively, the measurement resolution is 0.813μm. When using step multimode fiber with core diameter of 40μm in place of single-mode fiber as the displacement fiber, the displacement detection range reaches 50μm which is double that of the reported fiber SPR micro displacement sensor. The proposed fiber SPR micro displacement sensor well solved the two bottleneck problems above, which can be used in the field of micro displacement measurement of structural health monitoring.

High sensitivity refractive index sensor with wide detection range and high linearity based on LSPR in hollow-core anti-resonance fiber

A high sensitivity refractive index sensor based on local surface plasmon resonance in hollow-core anti-resonance fiber with wide detection range and high linearity is proposed. Gold nanowires are filled in two symmetric cladding tubes of the hollow-core anti-resonance fiber, and analyte is filled in the fiber core area. A full vectorial finite element method is used to design and analyze the hollow-core anti-resonance fiber sensor based on local surface plasmon resonance. High average wavelength sensitivity around 14996.81 nm/RIU is achieved in a wide refractive index detection range of 1.28–1.44 with high linearity of 0.99991. The maximum figure of merits of the sensor reaches 139.78 RIU−1. This separate filling of analyte and sensitive material opens up convenience applications for microfluidic detection. Due to its high sensitivity, wide detection range and high linearity of response, the proposed refractive index sensor also has potential applications in environmental protection, food safety and biosensing.

High index core flat fiber surface plasmon resonance bio-sensor.

Due to tremendous design flexibility and ease of light control capability, the photonic crystal fiber offers efficient, flexible, and miniaturized plasmonic biosensors with attractive features. In this work, a high index (GeO2 doped silica) core flat fiber is proposed and analyzed for RI sensing ranging from 1.53 to 1.60. A rectangular analyte channel is created on top of a flat fiber to better handle the liquid analyte. To introduce the plasmonic effect, TiO2 and gold are deposited to the analyte channel. The sensing performance is carried out for two operating wavelengths, as two peaks are obtained for each analyte. The second operating wavelength shows better sensing performance than the first one. However, the proposed sensor offers average wavelength sensitivity of 5000 nm/RIU with a sensor resolution of 2×10-05 RIU. In addition, the proposed sensor shows identical linearity, which is quite rare in prior sensors. Moreover, the proposed flat sensor provides outstanding detection accuracy of 0.01nm-1, detection limit of 79.28 nm, signal to noise ratio of -4.1497dB, and figure of merit of 50RIU-1. Owing to outstanding sensing performance and a unique detection range, this sensor can be effectively used in biological and organic analyte sensing applications.

Fiber SPR two-dimensional micro displacement sensor based on the coaxial double waveguide with a conical structure.

Fiber SPR micro displacement sensor cannot be used for two-dimensional displacement sensing at present. In this paper, we proposed and demonstrated a fiber SPR two-dimensional micro displacement sensor based on the coaxial double waveguide with a conical structure. The coaxial double waveguide is fused into a cone as the light injection fiber, and two different forms of outgoing light fields can be obtained through two cores of the fiber. The horn shaped light field emitted by the ring core of the coaxial double waveguide can cooperate with the sensing fiber to realize the micro displacement sensing in the x-axis direction. And the straight beam emitted by the middle core of the coaxial double waveguide can cooperate with the sensing fiber to realize the micro displacement sensing in the y-axis direction. Through simulation analysis and experimental test, its average wavelength sensitivity and light intensity sensitivity of the x-axis displacement are 0.0537nm/µm and 0.000124a.u./µm, respectively. And that of the y-axis displacement are 0.315nm/µm and 0.00277a.u./µm, respectively. The proposed fiber sensor realizes the two-dimensional displacement sensing based on SPR, which can be widely used in the fields of two-dimensional micro displacement measurement and two-dimensional position precision positioning.

Optical fiber current sensing based on a macro-bending no-core fiber structure and magnetic fluid

An all fiber current sensor based on magnetic fluid (MF) is proposed. The sensing structure is composed of a piece of no-core fiber (NCF) spliced between two sections of single mode fiber. The MF is used as the cladding of NCF. The sensing principle is based on the cladding mode interference. In order to improve the sensitivity, a bent-melt taper NCF is proposed as the sensing probe for the first time to increase the evanescent field. As a comparison, the sensitivities of optical fiber current sensors with straight NCF, bent NCF, and bent-melt taper NCF are measured in this paper. According to the experimental results, the sensitivities of optical fiber current sensor with bent-melt taper NCF are the highest among the three. The average wavelength sensitivity is 10.48 nm/A with the corresponding measurement range of 0–0.8 A, and the maximum standard deviation is 0.27 nm. The average total relative transmission loss sensitivity is 17.28 dB/A with the corresponding measurement range of 0–0.6 A, and the standard deviation of the maximum loss is 0.31 dB. The proposed sensor has good repeatability, reversibility and high sensitivity.

Research on D-Shape Open-Loop PCF Temperature Refractive Index Sensor Based on SPR Effect

PCF (Photonic crystal fiber) temperature refractive index sensor based on SPR effect with the new double membrane open-loop structure is proposed. The inner surface of such PCF&#x2019;s open-loop structure is plated with a layer of 70 nm gold film, and a layer of 20 nm SiO <inline-formula><tex-math notation="LaTeX">$_{2}$</tex-math></inline-formula> film is coated on the gold film, which could effectively prevent the gold film from oxidation corrosion. Besides, the open loop could reduce the production cost, and it could form two energy channels with nearby air holes, promoting the leakage of core energy to plasma mode and enhancing the SPR effects. The ethanol could be adopted as the temperature sensing solution, to measure the refractive index sensing of the solution to be measured. Numerical simulation is carried out based on the full vector finite element method, and the simulation results indicate that the average wavelength sensitivity of refractive index sensing could reach 3330 nm/RIU, and the wavelength sensitivity of temperature sensing could reach 0.912 nm/<inline-formula><tex-math notation="LaTeX">$^{\circ }$</tex-math></inline-formula> C, and a maximum figure of merit (FOM) of 102 which is approximately four times larger than that of the similar reported PCF-SPR sensors in the literature. The simulation results show that D-shape open-loop photonic crystal fiber has the potential application prospect on the temperature and refractive index sensing.

A novel photonic crystal fiber refractive index sensor with ultra wide detection range based on surface plasmon resonance effect

In this paper, a novel photonic crystal fiber (PCF) refractive index (RI) sensor based on surface plasmon resonance (SPR) effect is proposed. With the full vector finite element method, the SPR-PCF RI sensor is designed, and the mode coupling effects between the X-polarization (X-pol) and Y-polarization (Y-pol) core modes and second-order surface plasmon polariton modes are analyzed. The simulation results show that the structure parameters of the proposed PCF have significant influences on the resonance wavelength drift and wavelength sensitivity (WS). Finally, in the RI range of 1.32 ~ 1.48, the average WSs of the X-pol and Y-pol core modes can reach − 4735.83 nm/RIU and − 4525.83 nm/RIU, respectively. Moreover, the maximum resolution (R) and figure of merits (FOM) of the X-pol and Y-pol core modes are 4.71 × 10−6 and 4.65 × 10−6 RIU, and 134 and 177 RIU−1, respectively. Compared with other reported results, the proposed SPR-PCF RI sensor can achieve wide detection range, high average WS, good linearity, high R, and large FOM, so it will have important applications in the fields of biochemistry, medicine, and environmental science.

High Sensitivity Surface Plasmon Resonance Sensor Based on a Ge-Doped Defect and D-Shaped Microstructured Optical Fiber.

In this work a plasmonic sensor with a D-Shaped microstructured optical fiber is proposed to detect a wide range of analyte refractive index by doping the pure silica core with distinct concentrations of Germanium Dioxide , causing the presentation of high spectral sensitivity. In this case, the fiber is shaped by polishing a coating of , on the region that will be doped with , in the polished area, a thin gold layer, which constitutes the plasmonic material, is introduced, followed by the analyte, in a way which the gold layer is deposited between the . and the analyte. The numerical results obtained in the study shows that the sensor can determine efficiently a range of 0.13 refractive index units , with a limit operation where varies from 1.32 to 1.45. Within this application, the sensor has reached an average wavelength sensitivity of up to . With this level of sensitivity, the D-Shaped format and wide range of detection, the proposed fiber has great potential for sensing applications in several areas.