Integrated Additive and Subtractive Manufacturing of Glass Photonic Sensors for Harsh Environment Applications

Research and development in advanced manufacturing for sensors and devices fabrication is continuously changing the world, assisting to giving sensing solutions in the physical, chemical and biological fields. Specifically, many modern engineered systems are designed to operate under extreme conditions such as high temperature, high pressure, corrosion/erosion, strong electromagnetic interference, heavy load, long reaching distance, limited space, etc. Very often, these extreme conditions not only degrade the performance of the system but also impose risks of catastrophic failures and severe consequences. To perform reliably under these harsh conditions, the materials and components need to be properly monitored and the systems need to be optimally controlled. However, most existing sensing technologies are insufficient to work reliably under these harsh conditions. Innovations in sensor design, fabrication and packaging are needed to address the technological challenges and bridge the capability gaps. Optical fiber sensors have been widely researched and developed for energy, defense, environmental, biochemical and industry sensing applications. In general, optical fiber sensors have a number of well-known advantages such as miniature in size, high sensitivity, long reaching distance, capability of multiplexing and immunity to electromagnetic interference (EMI). In addition, optical fiber sensors are capable of operating under extreme environment conditions, such as high temperature, high pressure, and toxic/corrosive/erosive atmospheres. However, optical fiber sensors are also fragile and easy to break. It has been a challenging task to fabricate and package optical fiber sensors with predicable performance and desired reliability under harsh conditions. The latest advancements in high precision laser micromachining and three-dimensional (3D) printing techniques have opened a window of opportunity to manufacture new photonic structures and integrated sensing devices that deliver unprecedented performance. Consequently, the optical sensor field has quietly gone through a revolutionary transition from the traditional discrete bulk optics to today’s devices and structures with enhanced functionalities and improved robustness for harsh environment applications. Driven by the needs for sensors capable of operating in harsh environments, integrated additive and subtractive manufacturing (IASM) for glass photonics sensor fabrication process has been proposed and developed. In this dissertation, a series of high-performance optical fiber sensors were proposed and fabricated. In addition, several significant sensing measurements (e.g., pressure, temperature, refractive index variation) of the proposed sensors and structures with enhanced robustness were demonstrated in this dissertation. To realize measurement of above parameters, different working principles were studied, including mechanical deflection, light-material interaction and utilizing properties of fluidics. The sensing performance of the fabricated sensors and structures were characterized to demonstrate the capabilities of the developed IASM process on advanced manufacturing of glass photonic sensors with specific geometry and functions, and the realization for information integrated manufacturing purpose

Novel Specialty Optical Fibers and Applications

Novel Specialty Optical Fibers and Applications focuses on the latest developments in specialty fiber technology and its applications. The aim of this reprint is to provide an overview of specialty optical fibers in terms of their technological developments and applications. Contributions include:1. Specialty fibers composed of special materials for new functionalities and applications in new spectral windows.2. Hollow-core fiber-based applications.3. Functionalized fibers.4. Structurally engineered fibers.5. Specialty fibers for distributed fiber sensors.6. Specialty fibers for communications

A Review of Multimode Interference in Tapered Optical Fibers and Related Applications

In recent years, tapered optical fibers (TOFs) have attracted increasing interest and developed into a range of devices used in many practical applications ranging from optical communication, sensing to optical manipulation and high-Q resonators. Compared with conventional optical fibers, TOFs possess a range of unique features, such as large evanescent field, strong optical confinement, mechanical flexibility and compactness. In this review, we critically summarize the multimode interference in TOFs and some of its applications with a focus on our research project undertaken at the Optoelectronics Research Centre of the University of Southampton in the United Kingdom

Optic-Fiber Temperature Sensor

As an important parameter in industry, agriculture, biomedical, and aerospace, temperature possesses a significant position for the development of our society. Thus, it has become a hot point to develop novel sensors for temperature monitoring. Compared with traditional electronic sensors, optical fiber sensors break out for the compact structure, corrosion resistance, multiplex and remote sensing capability, cheap prices, and large transmission capacity. Especially the phase modulation type optical fiber sensors attract much attention for the fast and accurate measurement of the external parameters in a large dynamic measurement range. In this work, we review the optical fiber Mach-Zehnder interferometer (MZI) for temperature sensing which is widely used these years. The fundamental principles of MZI fiber sensors are proposed and discussed to further understand MZI. Different kind of structures for temperature sensing of recent years are summarized as several typical MZI categories and their advantages and disadvantages are indicated separately. Finally, we make a conclusion of the MZI temperature sensing and several methods typically to realize the MZI in practical application for the readers

Micro-/Nano-Fiber Sensors and Optical Integration Devices

The development of micro/nanofiber sensors and associated integrated systems is a major project spanning photonics, engineering, and materials science, and has become a key academic research trend. During the development of miniature optical sensors, different materials and micro/nanostructures have been reasonably designed and functionalized on the ordinary single-mode optical fibers. The combination of various special optical fibers and new micro/nanomaterials has greatly improved the performance of the sensors. In terms of optical integration, micro/nanofibers play roles in independent and movable optical waveguide devices, and can be conveniently integrated into two-dimensional chips to realize the efficient transmission and information exchange of optical signals based on optical evanescent field coupling technology. In terms of systematic integration, the unique optical transmission mode of optical fiber has shown great potential in the array and networking of multiple sensor units.In this book, more than ten research papers were collected and studied, presenting research on optical micro/nanofiber devices and related integrated systems, covering high-performance optical micro/nanofiber sensors, fine characterization technologies for optical micro/nanostructures, weak signal detection technologies in photonic structures, as well as fiber-assisted highly integrated optical detection systems

Tapered Optical Microfibre Based Structures for Sensing Applications

There has been an increasing demand in recent years from a wide variety of industries for sensors which combine high sensitivity, fast response, compact size and low power consumption. Tapered optical microfibres can generate easily accessible evanescent fields with a large intensity and short decay distance which make microfibres very suitable candidates as the basis of sensors to suit a variety of application areas. In this thesis, experimental research is presented concerning the development of sensors using structures based on tapered optical microfibres, with a particular emphasis on biochemical sensing applications. Light propagation along an optical microfibre depends on its shape, diameter and surface roughness. A microfibre fabrication setup developed as a key prerequisite to the research undertaken, that utilized an adapted microheater brushing and tapering technique is described. The setup allows for the fabrication of microfibres and related structures with controllable taper shapes and diameters. There is a tradeoff between sensitivities and microfibre diameters (which directly affects the robustness of the microfibre structures) for microfibre based sensors. To mitigate this tradeoff, two microfibre based structures were chosen and investigated for sensor development in the research reported in this thesis. The first structure was an optical microfibre coupler. Such an optical microfibre coupler, which has environment dependent coupling coefficients in addition to easily accessible evanescent fields, is a simple and efficient structure for sensing. A refractive index sensor with a maximum sensitivity of 4155 nm/RIU was developed using an optical microfibre coupler. Utilizing the structure’s refractive index sensitivity, a humidity sensor was developed by coating a microfibre coupler with a layer of humidity sensitive polymer. A biosensor was also developed by immobilizing a bio-receptor on the surface of a packaged microfibre coupler. The ability of the developed biosensor to detect the specific binding between an antibody-antigen pairing for potential applications in clinical diagnostics was demonstrated and is reported in this thesis. The second structure was a tapered optical microfibre which incorporates gold-silver alloy nanoparticles. By immobilizing nanoparticles onto the surface of a tapered optical. microfibre to generate localized surface plasmon resonances, sensitivity enhancement can be achieved for microfibres with relatively large diameters, which has the benefit of being more mechanically robust. The use of gold-silver alloy nanoparticles with different alloy formulations can offer the extra advantage of tunable physicochemical properties. The localized surface plasmon resonance effects were investigated and compared for sensor samples incorporating nanoparticles with different alloy formulations. As an example of a sensing application using the structure, a novel pH sensor was demonstrated by coating the immobilized nanoparticles with a pH sensitive polyelectrolyte multilayer film.

Fiber Optic Sensors and Fiber Lasers

The optical fiber industry is emerging from the market for selling simple accessories using optical fiber to the new optical-IT convergence sensor market combined with high value-added smart industries such as the bio industry. Among them, fiber optic sensors and fiber lasers are growing faster and more accurately by utilizing fiber optics in various fields such as shipbuilding, construction, energy, military, railway, security, and medical.This Special Issue aims to present novel and innovative applications of sensors and devices based on fiber optic sensors and fiber lasers, and covers a wide range of applications of optical sensors. In this Special Issue, original research articles, as well as reviews, have been published