Micro-opto-mechanical pressure sensor via ring resonator-based Mach–Zehnder interferometer

A microscale opto-mechanical pressure sensors was studied using a combination design of silicon microring resonator and Mach–Zehnder interferometer placed on the middle of the pliable squared diaphragm fabricated from silicon-polydimethylsiloxane layers. The outward displacement and deflection of the diaphragm in z-directions along the x- and y-axes were calculated using the finite element method. The optical transfer function of proposed layout was derived using the delay line signal approach. The optimum geometrical parameters of the system and a critical coupling condition were determined for pressure sensing application and an extended quasi-FSR as large as 108 nm with quality factor of 4752 was realized. The performance of the sensor in the range of 0–225 kpa was studied based on the spectral shift of output resonance peaks due to the applied shear stress on the diaphragm. The sensitivity and a minimum detectable pressure of proposed is calculated to be 0.38 nm/kPa and 50 pa, respectively. The proposed pressure sensor fulfills the expectations of microscale size, high precision, and high sensitivity, and this sensor potentially can be used as high-performance devices in the precision Instrumentation, aircrafts technology as well as harsh environments

Influence of coating thickness of polyimide for moisture sensing

This work focused on the effect of existence of polyimide coated fibre Bragg grating (FBG) for moisture sensing in stingless bee. The moisture sensitive material namely polyimide (PI) was used to improve the sensitivity of the fibre optic sensor. By taking the benefits from amine groups in 3-(aminopropyl) triethoxysilane (APTES), PI is coated onto the segment of FBG through covalent interaction. Different thickness of PI coated FBG as well as determination and optimization of the designated sensor has been done. 3 layers of polyimide coating were used to improve the sensitivity of moisture sensing, and the sensitivity of coated fibre been analysed

Influence of coating thickness of polyimide for moisture sensing

This work focused on the effect of existence of polyimide coated fibre Bragg grating (FBG) for moisture sensing in stingless bee. The moisture sensitive material namely polyimide (PI) was used to improve the sensitivity of the fibre optic sensor. By taking the benefits from amine groups in 3-(aminopropyl) triethoxysilane (APTES), PI is coated onto the segment of FBG through covalent interaction. Different thickness of PI coated FBG as well as determination and optimization of the designated sensor has been done. 3 layers of polyimide coating were used to improve the sensitivity of moisture sensing, and the sensitivity of coated fibre been analysed

Doping effect numerical comparison of band gap energy and active region range for GaN and GaAs based semiconductor

This work reports the effect of doping concentration on the energy-band structure of semiconductor materials. The research focuses on the resultant values of bandgap energy and its depletion region (length/area), based on the initial concentrations of doping which are the donors and acceptors. The energy-band diagram is simulated by initializing the various materials’ properties of Gallium Nitride (GaN) and Gallium Arsenide (GaAs), and solving the Poisson’s equation derived from Maxwell’s equation. The equation is solved by applying the finite difference method (FDM) and using the Newton-Raphson method. Both of these materials are compared with different doping concentrations (1x1013cm-3-1x1017cm-3). Taking the GaAs properties as the controlled variable, the band structure is validated with literature findings. The measured band gap energy of GaN changes from 1.5215eV to 7.6689eV, and GaAs, from 1.1330eV to 5.6431eV. It increases with the proportion to the doping concentration increments. However, when obtaining both of the spatial active regions for GaN and GaAs, it reduce from (1.9990μm-0.0790μm)x1μm2 and from (1.9990μm-0.0890μm)x1μm2 respectively. The findings show the effect of doping concentration on the semiconductor energy-band structure. Thus, the numerical system is expected to be used as the determination of the internal quantum efficiency, and the output spectrum of light-emitting diode (LED) chip

Geometrical analysis of light-emitting diode for enhancing extraction efficiency

A non-uniform current spreading in the current spreader can greatly reduce the effciency of the light-emitting diode (LED). The effects of the electrode contact area to the spreading layer towards extraction effciency of LED chips is analysed in analytical simulations. Length of current spreading and light extraction effciency is analysed for variation of contact area. The contact area value is varied by changing the shape of the electrode and the value of width of contact area. The increase in contact area decreases light extraction effciency as more light are absorbed by the bottom electrode surface. The effective current spreading length for Indium Tin Oxide (ITO) of thickness 300nm is 36.44µm. The 6 strips ‘fork’ design is the most optimum. The design has the most area for photons produced in active region to escape without reducing the area cover with current density. This enables the chip to has more extraction effciency with more uniform current spreading

Temperature sensing with Fibre Bragg Grating and No-Core Fibre

In this paper, optical fibre Bragg grating (FBG) and no-core fibre (NCF) sensors have been investigated for their performance in the temperature range 30–100 �C. The change in Bragg and NCF wavelengths with temperature changes was used to determine the performance and sensitivity of the sensors. The gradient of D kFBG and kNCF versus temperature leads the sensitivity of the FBG and NCF sensors as 23.97 and 20.08 pm/�C, respectivel

Carbon ion characterization in arc discharge plasma

The objective of this study is to determine the energy of carbon ion in different environment and pressures. The purpose of determination the energy of carbon ion is to get better knowledge regarding on the fabrication of different type of carbon nanostructures. Carbon nanostructures become more useful due to their unique carbon elements. They can form ball-shaped, fullerenes and cylindrical nanotubes. The energy of carbon ion can be obtained by measuring the ion track sizes on the CR-39 target. Solid state nuclear track detector (SSNTD) was used to track the charged nuclear particles, such as alpha particles or fission fragments. In this study, arc discharge plasma generated by graphite electrode were chosen to produce carbon nanostructures and the CR-39 were exposed to energetic carbon ion under different environment and pressures. The energetic carbon ion was etched by 6.25 M of NaOH solution for 8 hours. The temperature was maintained at (72±1) °C to ensure the etching process going smoothly. The ion tracks was observed under optical microscope and the diameter of ion track were measured. The energy was determined from the diameter obtained by using the related formula. The energy of carbon ion is influenced by the diameter ion track. High values of carbon ions energy are observed in hydrogen ambient environment as compared to air ambient environment under same ambient pressures and the energy of carbon ions decrease with increase in the ambient pressure

Doping effect on bandgap energy and luminescence spectrum for AlN-based semiconductor

This ongoing work reports the heavy doping effect on the Aluminum Nitride (AlN) semiconductor (SC) material, illustrated via its energy-band structure (EBS). The research correlates the bandgap energy (BE) and depletion region (DR), which are then applied to the estimation of light-emitting diode (LED) luminescence spectrum (LS). The measurements are compared with different dopant concentrations (1 × 1018 cm−3 –1 × 1021 cm−3). Having the Gallium Arsenide (GaAs) properties as the controlled variable, the EBS is validated with literature findings. The measured band gap energy of AlN shifts from 6.2435 to 6.2326 eV. It decreased as the dopant concentration increased. However, the active spatial regions, reduced from (1.0250 × 10−1 to 4.5000 × 10−3 µm) × 1 µm2. The findings are compared with the output LS of LED using the same SC material. The changes in BE and DR are consistent with the LS peak intensity wavelength and relative intensity to all the chosen doping concentrations. Though acquiring this consistency, an extensive discussion with collaboration in material science studies will further strengthen the understanding regarding these behaviours

Optical bistability in all-pass mobius configuration microring resonator

A novel design of microring resonator called all-pass Mobius ring resonator is used to study optical bistability effect and spectral transmission for all-optical switching application with clockwise hysteresis loop operation. The bright soliton pulse is applied as the input source of the system. The propagation of the pulses within the system is simulated using the transfer matrix analysis. The all-pass Mobius ring resonator is able to operate under high nonlinearity as it has longer propagation length per roundtrip. The all-pass Mobius provides low transmission peak power of 3.65 mW as compared to the conventional all-pass configuration. The output-to-input relation of both design shows that the Mobius configuration is able to generate a higher hysteresis loop width of the bistable signal from 15.79 mW to 18.10 mW input power. The switching power of the optical bistability in Mobius configuration is 3.67 mW for threshold power of 16.95mW. This work shows the Mobius configuration is more suitable to be used for all-optical switching application as compared to the conventional all-pass ring resonator configuration

Glucose and sucrose analysis in daucus carota extract using optical tapered fibre sensor with GOU-AuNP composite layer synthesization

Tapered single-mode fibre (SMF) immobilized with glucose oxidase enzyme (GOD) and gold nanoparticles (AuNP) for the recognition of glucose and sucrose elements have been proposed. A tapered fibre was fabricated using a flame heating technique to improve the sensitivity of the fibre-based sensor. By taking advantage of amine groups in 3-aminopropyl triethoxysilane (APTES), GOD and AuNP are functionalized onto the tapered region of SMF through covalent interaction. The developments of the immobilized tapered fibre sensor for the analysis of glucose and sucrose concentration in different concentrations of the solution and types of carrots extracts were discussed in this paper. The solution concentrations of 0.1, 0.2, and 0.3 g/ml of glucose and sucrose were used to analyze the sensitivity of the fibre sensor. The extracts of baby carrots, imported carrots, and organic carrots were used to determine the existence of glucose and sucrose in these carrots. We demonstrated the sensitivities of GOD-immobilized fibre for 0.00672, 0.00722, 0.00902, and 0.00921 a.u/nm in terms of their glucose solutions, baby carrots, imported carrots, and organic carrots, respectively. Meanwhile, the sensitivities of AuNP-immobilized fibre were found to be 0.000030, 0.000026, 0.000012, and 0.000024 a.u/nm, respectivel