Norhana Arsad

Advances in Bio-Tactile Sensors for Minimally Invasive Surgery Using the Fibre Bragg Grating Force Sensor Technique: A Survey

The large interest in utilising fibre Bragg grating (FBG) strain sensors for minimally invasive surgery (MIS) applications to replace conventional electrical tactile sensors has grown in the past few years. FBG strain sensors offer the advantages of optical fibre sensors, such as high sensitivity, immunity to electromagnetic noise, electrical passivity and chemical inertness, but are not limited by phase discontinuity or intensity fluctuations. FBG sensors feature a wavelength-encoding sensing signal that enables distributed sensing that utilises fewer connections. In addition, their flexibility and lightness allow easy insertion into needles and catheters, thus enabling localised measurements inside tissues and blood. Two types of FBG tactile sensors have been emphasised in the literature: single-point and array FBG tactile sensors. This paper describes the current design, development and research of the optical fibre tactile techniques that are based on FBGs to enhance the performance of MIS procedures in general. Providing MIS or microsurgery surgeons with accurate and precise measurements and control of the contact forces during tissues manipulation will benefit both surgeons and patients.

Development of Phase Detection Schemes Based on Surface Plasmon Resonance Using Interferometry

Surface plasmon resonance (SPR) is a novel optical sensing technique with a unique ability to monitor molecular binding in real-time for biological and chemical sensor applications. Interferometry is an excellent tool for accurate measurement of SPR changes, the measurement and comparison is made for the sensitivity, dynamic range and resolution of the different analytes using interferometry techniques. SPR interferometry can also employ phase detection in addition to the amplitude of the reflected light wave, and the phase changes more rapidly compared with other approaches, i.e., intensity, angle and wavelength. Therefore, the SPR phase interferometer offers the advantages of spatial phase resolution and high sensitivity. This work discusses the advancements in interferometric SPR methods to measure the phase shifts due to refractive index changes. The main application areas of SPR sensors are demonstrated, i.e., the Fabry-Perot interferometer, Michelson interferometer and Mach-Zehnder interferometer, with different configurations. The three interferometers are discussed in detail, and solutions are suggested to enhance the performance parameters that will aid in future biological and chemical sensors.

Intra-Cavity Spectroscopy Using Amplified Spontaneous Emission in Fiber Lasers

Fiber laser sources offer interesting possibilities for gas sensors since they can operate over an extended wavelength range, encompassing the near-IR absorption lines of a number of important gases but a major problem is that overtone absorption lines of gases in the near-IR are relatively weak. In order to enhance sensitivity, we present here a simple method of intra-cavity absorption spectroscopy (ICAS) which makes use of the amplified spontaneous emission (ASE) already present within a fiber laser cavity. The ASE also provides a convenient broadband source for the simultaneous interrogation of several gases within the gain-bandwidth of the fiber laser. The key principle is based on adjusting the cavity attenuation to select an appropriate inversion level where the fiber gain curve is flat. Under this condition, the ASE undergoes multiple circulations within the fiber laser cavity, enhancing the effective path-length of a gas cell placed within the laser cavity. A theoretical model of system operation is given and we have experimentally demonstrated the principle of operation with acetylene and carbon dioxide using a simple erbium fiber laser system containing a 6 cm path-length, fiber coupled, intra-cavity, micro-optic gas cell. We have experimentally simultaneously observed 16 absorption lines for 1% acetylene gas in the 1530 nm region and detected the very weak carbon dioxide lines in this same wavelength region. A path length enhancement of in the linear regime has been demonstrated transforming the 6 cm micro-optic cell into an effective path length of m. We also demonstrate how the enhancement factor may be calibrated by use of a simple fiber-optic interferometer. Apart from the OSA, all components are inexpensive and the system is very simple to construct and operate.

An assessment study of absorption effect: LED vs tungsten halogen lamp for noninvasive glucose detection

Noninvasive glucose monitoring development is critical for diabetic patient continuous monitoring. However, almost all the available devices are invasive and painful. Noninvasive methods such as using spectroscopy have shown some good results. Unfortunately, the drawback was that the tungsten halogen lamps usage that is impractical if applied on human skin. This paper compared the light emitting diode (LED) to traditional tungsten halogen lamps as light source for glucose detection where the type of light source plays an important role in achieving a good spectrum quality. Glucose concentration measurement has been developed as part of noninvasive technique using optical spectroscopy. Small change and overlapping in tungsten halogen results need to replace it with a more convenient light source such as LED. Based on the result obtained, the performance of LED for absorbance spectrum gives a significantly different and is directly proportional to the glucose concentration. The result shows a linear trend and successfully detects lowest at 60 to 160 mg/dL glucose concentration.

RFID impacts on barriers affecting lean manufacturing

Purpose Lean manufacturing is one of the leading paradigms for fast and proficient manufacturing but its proper implementation is a foremost task due to certain barriers affecting lean and can be handled when utilized with RFID technology. With this aspect in view, the purpose of this paper is to enlighten and present a thorough literature study that can show how RFID-based lean manufacturing is helpful for handling barriers affecting lean manufacturing in light of previous literature available. Design/methodology/approach In order to achieve this purpose a systematic literature review is conducted to justify the impacts of RFID technology for handling barriers. The aim of this systematic literature review is to initially find the barriers affecting lean implementation and then to explain the properties of RFID-based lean manufacturing which are highly feasible to handle detected barriers. Findings An interrelation is generated in this study which provides a clear indication that the properties of RFID carry significant effects to handle detected barriers in the operational, managerial and financial regime of manufacturing companies. The detected barriers that affect lean implementation are company’s cultures, top management commitment, poor employee administration, lack of finances, unbalanced inventory control, unstable customer handling and longer lead times. The properties of RFID-based lean manufacturing like operational visibility, inventory control, production control, minimized lead times and the real-time data information (to facilitate top management and employees on shop floor) are extremely helpful to control these barriers. Originality/value The originality of this study is the provision of clarity provided to both academicians and practitioners by citing and utilizing previous research studies which undoubtedly indicates positive impacts of RFID on lean implementation.

Performance of 18 channel CWDM system with inline Semiconductor Optical Amplifier

Semiconductor Optical Amplifier (SOA) is used for a 2.5Gbps Coarse Wavelength Division Multiplexing (CWDM) transmission in O to L-band (1271-1611 nm). Analysis of the proposed topology is conducted using Optisystem software. In this paper, discussions on the gain spectrum and the quality of signal of an optically amplified 18 channel system are provided. A wideband travelling wave SOA which operates as an inline amplifier resulted in wide 3 dB bandwidth of 200 nm. The overall quality of signal at the receiver is evaluated with the Q factor value. Better performance based on Q factor analysis is obtained at larger lengths of the first fiber span and a flat gain over 11 CWDM channels is obtained.

Binding Affinity of a Highly Sensitive Au/Ag/Au/Chitosan-Graphene Oxide Sensor Based on Direct Detection of Pb2+ and Hg2+ Ions

The study of binding affinity is essential in surface plasmon resonance (SPR) sensing because it allows researchers to quantify the affinity between the analyte and immobilised ligands of an SPR sensor. In this study, we demonstrate the derivation of the binding affinity constant, K, for Pb2+ and Hg2+ ions according to their SPR response using a gold/silver/gold/chitosan–graphene oxide (Au/Ag/Au/CS–GO) sensor for the concentration range of 0.1–5 ppm. The higher affinity of Pb2+ to binding with the CS–GO sensor explains the outstanding sensitivity of 2.05 °ppm−1 against 1.66 °ppm−1 of Hg2+. The maximum signal-to-noise ratio (SNR) upon detection of Pb2+ is 1.53, and exceeds the suggested logical criterion of an SNR. The Au/Ag/Au/CS–GO SPR sensor also exhibits excellent repeatability in Pb2+ due to the strong bond between its functional groups and this cation. The adsorption data of Pb2+ and Hg2+ on the CS–GO sensor fits well with the Langmuir isotherm model where the affinity constant, K, of Pb2+ and Hg2+ ions is computed. The affinity of Pb2+ ions to the Au/Ag/Au/CS–GO sensor is significantly higher than that of Hg2+ based on the value of K, 7 × 105 M−1 and 4 × 105 M−1, respectively. The higher shift in SPR angles due to Pb2+ and Hg2+ compared to Cr3+, Cu2+ and Zn2+ ions also reveals the greater affinity of the CS–GO SPR sensor to them, thus supporting the rationale for obtaining K for these two heavy metals. This study provides a better understanding on the sensing performance of such sensors in detecting heavy metal ions.

Flat gain, wide bandwidth of in-line semiconductor optical amplifier in CWDM Systems

Abstract Semiconductor optical amplifier (SOA) is one of the commonly used amplifiers in optical networks. This paper reviews the SOA implementation in coarse wavelength division multiplexing (CWDM) systems, which includes the explanation of the fundamental concepts such as the configuration, principle of operation as amplifiers, and the performance in different CWDM topologies. Simulation using OptiSystem software was carried out to determine the gain saturation at high input power and longer wavelengths. It shows that SOA implementation in CWDM networks is capable of providing flat gain for 40 nm wavelength span.

Impact of coupled resonator geometry on silicon-on insulator wavelength filter characteristics

We have analyzed and discussed the issues arising in the design of Silicon — on — Insulator (SOI) wavelength filters with different types of device geometry. Microring and microdisk geometries have been chosen as the device configurations and in order to demonstrate the device performance and potential, Free Spectral Range (FSR), and Q-factor values are computed. Studies of the transmittance characteristics are carried out using Finite-Difference Time-Domain (FDTD) methods by RSOFT Software. Results show that the microring-based wavelength filter has a FSR of 1.4 THz and a Q-factor value of 486. On the other hand, the microdisk based filter has a broader FSR with slightly smaller Q-factor.

A Novel Technique Employing Tapered Fiber Bragg Grating to Solve the Axial/Transverse Forces Crosstalk in Microsurgical Instruments

This paper demonstrates the capability of retinal microsurgical instruments constructed with customized fiber Bragg gratings (FBGs) sensors to completely decouple the transverse and axial force components. In contrast to the constantly shifting Bragg wavelength, FBG bandwidth can only be tuned when a nonuniform strain/temperature distribution is applied. Using a tapered FBG (TFBG) at the neutral axis of the instrument makes the bandwidth tune-ability possible by applying forces both transversely and axially, while the bandwidth of the outer/lateral standard FBG (SFBG) due to the fiber symmetry remains insensitive to axial forces. Therefore, the crosstalk (transverse forces) in the TFBG can be easily filtered out when mixed forces are applied simultaneously. Tapered fiber mode analysis is carried out to calculate the local modes and is used in the analytic coupled-mode solution. Transfer-matrix method, then, is developed to analyze the reflected spectrum of the TFBG. We provide a developed mathematical model algorithm to show how force vectors can be measured. Tuning the reflected bandwidth is directly corresponding to the amount of the reflected optical power. Thus, the results show that the simulated needle sensors are able to measure transverse and axial forces with a sensitivity of 0.049 and 0.0026 dBm/mN, while the SFBG is insensitive to the axial forces. This novel method is applicable for microsurgical applications, i.e., vascular and cochlear implant surgeries and catheterization procedures.