Developments in Plastic Optical Fibers - Essay Example

Developments in plastic optical fibers and fiber optic sensors By Table of Contents Table of Contents 2 Part A 3 Introduction 3 Plastic Optical Fibers 4 Types of Optical Fiber 5 Quartz optical fiber 6 Glass optical fiber 6 Plastic optical fiber 6 Polymer-clad fiber 6 Types of Plastic Optical fiber 6 Comparison with Glass Fibers 7 Advantages of POF 8 Quick, Easy and Inexpensive Installations 8 High Bandwidth 9 Rugged and Strong 9 Protection against Electrical Noise 9 Simple Design 9 Extensively Used 10 Affordable 10 Disadvantages of POF 10 Applications of POFs 10 Future Prospects 11 Conclusion 11 Part B 13 Introduction 13 An overview of Optical Fiber Sensors 13 Basic Principles of Fiber Optic Sensors 14 Principle of Total Internal Reflection 16 Types of Sensors with respect to working 16 Bragg Grating Sensors 16 Distributed Sensing 16 Quasi-distributed Sensing 17 Other Approaches 17 Applications of Optical Fiber Sensors 18 Advantages in comparison with other sensors 18 The future of optical fiber sensors 19 Conclusion 20 References 20 Part A Introduction Plastic optical fiber (POF) has always been hiding in the background of fiber optics however they have been used for low speed and light short data connections. With the passage of time, it gained massive popularity among industries due to a greater interest given by research and development (R&D) sector. In fact, R&D has made possible for it to get higher performance to follow with its low cost and ease of installation (The FOA, 2008; Paschotta, 2014). This report presents a detailed analysis of plastic optical fiber. This report will discuss basic structure of plastic optical fiber, its working, its advantages and disadvantages. This report also discusses the future prospects of this technology. Plastic Optical Fibers As shown in figure 1, plastic optical fiber is huge central step-index fiber and its diameter is equal to 1 mm (millimeter). Hence, its huge size allows it to easily combine lots of light coming from various connectors and sources with less precision. In this scenario, the prices of standard connector are between 10% and 20% for glass fibers as well as closure is also as easy as cutting with a razor blade. In view of the fact that it is coated with the plastic so it makes it easy and rugged to install and connect deprived of fear of loss or damage. (The FOA, 2008; Paschotta, 2014) Figure 1Structure of Plastic Optical Fiber, Image Source: http://www.thefoa.org/tech/pof.htm Figure 2core of Plastic Optical Fiber, Image Source: (Industrial Fiber Optics, 2014) However, one of the major drawback of this media is that its performance is much lower than glass fiber. Additionally, its bandwidth is limited as well as it has a connection loss of approximately 0.15-0.2 dB per meter at 650 nm. On the other hand, it works fine when it is used for running short connection, for instance within a place for desktop connections up to 50 meters or inside of instruments. In this scenario, its most excellent usage is seen in automobile industry in which it has expanded a position with the innovative Flexray and MOST networks (The FOA, 2008; Paschotta, 2014). Its proven effectiveness for small distance connections make it an excellent choice for desktop LAN connections. For such connections, it can be installed in a few minutes with negligible training and tools. In future, it can be expected that its bandwidth will exceed to considerable level. However, its cost is reasonable as compared to copper. In fact, standards groups are currently looking at various choices for plastic fiber optics. It is believed that POF can be the following practical desktop connection (The FOA, 2008). Normally, the transmission is carried through fiber optic systems in the digital format. In other words, this transmission is sent and received in the shape of pulses. In this scenario, during its transmission a pulse through the fiber, undergoes a time-based spread called dispersion or temporal dispersion. Additionally, this dispersion can have serious impact on analogue communications, for the reason that it creates a misrepresentation in the waveform of the signal. Hence, in any transmission connection that is based an optical fiber there is a dispersion the parameter that measures the extreme bandwidth that an optical fiber can transmit (Zubia & Arrue, 2001). Types of Optical Fiber Normally, plastic optical fibers are made of material known as PMMA (Polymethyl methacrylate). Additionally, there are many other types of optical fiber and their specific features and properties are applied in different fields. Given below are some of the well-known types of optical fibers which are widely used in different area (Industrial Fiber Optics, 2014; Paschotta, 2014): Quartz optical fiber This type of optical fiber is appropriate for carrying long-distance transmissions. This type is further divided into two types. First type is known as single mode fiber that is commonly used for communications. And second type is known as multi-mode fiber that is widely used for office networks. Glass optical fiber Its type multi-component glass optical fiber is extensively employed together with plastic optical fiber for lighting. Plastic optical fiber It is the most commonly used optical fiber that is used for short-distance for motor vehicles and electronic appliances. Polymer-clad fiber This fiber comes with a quartz core and plastic cladding. Types of Plastic Optical fiber Up till now, new developments and advancements are taking place in the field of plastic optical fiber and new types of plastic optical fibers are being introduced such fluorinated and polycarbonate. In this scenario, polycarbonates and polystyrene are widely utilized for low-priced fiber-optic mass applications. In a typical scenario, a plastic optical fiber can contain a PMMA center enclosed by a fluorinated cladding, with a lesser refractive index. On the other hand, the center may be fixed with some index-raising agent. However, in order to attain high data rates, definite perfluorinated polymers like that poly (perfluoro-butenylvinyl ether) are used, for the reason that they can be processed at longer wavelengths and show much lower transmission losses, where receivers and transmitters as produced for glass fibers can be utilized. In addition, photonic crystal fibers is a comparatively novel and not yet commonly used development with plastic materials (Industrial Fiber Optics, 2014; Paschotta, 2014). Comparison with Glass Fibers In their article, (Paschotta, 2014) gives a good comparison of plastic optical fibers with glass fibers. According to author, POF greatly differs from glass fibers in many ways: Normally, the loss of various plastics optical fibers is smallest at observable wavelengths, or in case of perfluorinated polymers it can be near infrared (less than 1.3 millimeter). On the other hand, the loss of silica fibers minimum at greater than 1.5 μm, as well as various other glasses even at much higher wavelengths. It is an admitted fact that the data transmission with plastic optical fiber is limited to smaller area as compared to glass fibers. For instance, with a normal plastic optical fiber there are higher transmission losses i.e. 50 or even 100 dB/km, on the other hand the transmission loss with silica fibers is well below 1 dB/km (in case of single-mode fibers) or up to a few dB/m (in case of multimode fibers). Plastic optical fibers are believed to be very useful in case when light-emitting diodes are to be used as data transmitters for the reason that plastic optical fibers are normally multimode fibers with a high numerical aperture (e.g. 0.4), and a huge center (as discussed above it has a diameter of the order of 1 mm), hence it provides support for a wide variety of guided modes. On the other hand, in case of glass fibers, intermodal distribution can be reduced by making use of graded-index profile designs. However, it is clear that plastic optical fiber does not seem appropriate for single-mode guidance. Plastic optical fibers are computationally more flexible and strong. It is an admitted fact that their multimode guidance with high NA and a huge center significantly reduces the forbearances for connectors, in order that simple plastic components can be used and there is no need for additional or sophisticated training. Because of these causes, as well as not inexpensive ingredients, plastic optical fibers make allowance for considerable cost savings in numerous applications. Mechanically well protected glass fiber cables are much thicker and less lightweight than POF cables. At the present, the use of plastic optical fibers is increasing at rapid pace and its applications can be seen in a variety of areas for instance home networks, aircraft industry and the automotive. In addition, illumination is another significant application domain, which is gaining considerable benefits from the quick development of light-emitting diodes (Paschotta, 2014). Advantages of POF Plastic optical fibers are believed to be tremendously rugged dependable, due to these characteristics they are being adopted in a variety of fields such as in the residential, industrial and commercial networking market. Plastic optical fibers are also preferably appropriate for offering high-bandwidth developing solutions for instance IPTV as well as additional triple play services. As compared to traditional wiring such as Cat5 and Cat6 POF provides a number of advantages when these deployed for residential, and industrial and commercial networking (EZ, 2014): Quick, Easy and Inexpensive Installations As discussed above, the most important advantage of POF is that it can be used and installed a home builder, by making use of very basic tools and with little training. In view of the fact that plastic optical fiber presents easy to build connection hence it makes installations easy, simple, rapid and far more straight-forward than various other networking technologies. In addition, POF will decrease the price of truck rolls for broadband service providers for the reason that it is so fast, economical and easy to install. High Bandwidth It is expected that in the future POF will be able to offer a data rate of 1Gbps while maintaining the maximum quality of service to every office and home user. However, it presently offers data rates of equal to 100 Mbps. However, its current data rate makes it the most useful choice for 100 Mbps optical fast Ethernet networks in residential, industrial and commercial environments. Rugged and Strong Plastic optical fiber can be an excellent choice for the deployment in construction because it is a very durable and rugged technology that can be moved and turned deprived of any loss of bandwidth, loss of service, or damage to the cabling. Protection against Electrical Noise It is believed that POF is absolutely protected against electrical noise for the reason that it sends and receives data optically. In other words, plastic optical fibers can be installed even alongside electrical wiring. In this scenario, it is believed to be the most important advantage of POF especially in case of bandwidth-intensive applications, for instance multimedia data transmission, in order that the signal transmitted via plastic optical fiber will not damage or be destructively affected by outside noise. Simple Design Plastic optical fibers are believed to be an excellent choice for home/office designers and architects, for the reason that one POF cable capable of satisfying a wide variety of network media needs and varying requirements. At the present, plastic optical fiber cables are being used for point-to-point connections and up to 100 meters for 100 Mbps with more powerful POF cables with 0.3NA and up to 75 meters for 100 Mbps with 0.5NA cables. However, if someone wants to expand their network, they can use a repeater. Extensively Used Plastic optical fiber is not a new technology, it is already being used for a long time and is a proven technology in numerous industries as well as is already extensively utilized in the automotive industry. In fact, up till now this technology has been used in more than 20 million cars to carry high speed in-car infotainment. Affordable Plastic optical fibers are a cost effective solution for home and office users. In fact, devices and equipment such as EoPOF devices, plastic optical fiber cabling, fiber optic transceivers, connectors are perfect for builders and for broadband service providers who find it difficult to install innovative industrial and commercial and residential networking products under budget limitations (EZ, 2014). Disadvantages of POF Some of the disadvantages of Plastic optical fibers are outlined below (Polishuk, 2006; Paschotta, 2014): These cables are useful for only small distance communication so there is high loss during transmission. There are only a small number of providers of total systems Up till now there are no standards developed or inappropriate standards for this technology. As this technology is not very popular as compared to other media, so there is a lack of awareness and knowledge among users of how to design and install networks with POFs Inadequate or limited manufacturing, which does not allow the customers to realize the complete usefulness of POFs. High temperature fibers (approximately 125°C) Applications of POFs As compared to glass optical fibers which are mainly used in telecommunication sector, POFs are being used in many industries. At the present, automobile companies making excellent uses of this technology. It is an admitted fact that the automobile companies always search for the technologies that can help them make their product a huge success and POF is believed to be that killer technology for automobile industry which has offered many benefits for the automobile industry. Another most important usage of POF is in the field of computing because a wide variety of applications are currently being created for large data centers, supercomputers, server farms and all requiring a large number of interconnection over comparatively small distances sometimes within the range of 50 meters or less. In addition, due to its small size, resiliency to shock, low weight, and high bandwidth capabilities over short distances, POFs is currently truly being considered for use in tanks, aircraft, ships, missiles, helicopters and spacecraft (Polishuk, 2006). Future Prospects Without a doubt, POF is believed to be an innovative technology and sometimes it is being acknowledged as a disruptive technology. Normally, disruptive technologies are considerably cost effective and these technologies can be further developed by the established companies, however for the companies it is hard to decide that whether their effort will be worth the essential resources or how to promote the product. In addition, it is just a matter of time before the advantages of extensive production in the auto manufacturing begin to infuse medical instruments, consumer electronics and various other fields, and carry the cost structure and benefits of plastic optical fibers to stay in these sectors (Polishuk, 2006). Conclusion This report has discussed various aspects associated with POF. This report started with a brief introduction of POF and then it provided a detailed description of the working of this technology. This report has provided a detailed comparison of this technology with other technologies. The applications of POF are increasing with the passage of time. In fact, it is already being heavily used in automobile industry. And other industries are also looking for the ways to make effective use of this technology. It is expected that in the future the applications of this technology will further increase in other areas of life. Part B Introduction A few decades ago the emergence of fiber optical technology had revolutionized the communication and telecommunications industry. In fact, this revolution turned out to be a guiding map for production companies of this area and they started to develop techniques together with practical enhancements which resulted in excellent performance at much lower prices than those of alternate solutions. However, this revolution did not end at this point and it continued until the development of fiber optic sensors (also called optical fiber sensors) as a result of mixture of the fiber optic telecommunication product outgrowths with optoelectronic devices. In addition, these developments also established the basis of other opportunities which included the potential of substituting the majority of environmental sensors in presence currently and setting up all-inclusive marketplaces where sensors with similar competence do not exist (Jasenek, 2010). This basic purpose of this report is to present a detailed analysis of optical fiber sensors. This report discusses its working, principles and types. This report will also discuss the applications of optical fiber sensors. An overview of Optical Fiber Sensors Basically, optical fiber sensors are devices made up of fiber that are used for sensing some quantity, such as mechanical stress or temperature, however it also commonly used for measuring other quantities such as vibrations, displacements, acceleration, pressure, rotations (which are calculated with optical gyroscopes on the basis of the Sagnac effect), or absorptions of chemical properties. In addition, all these devices are based on almost similar principle and that is the light from a laser (which can be fiber laser with a single-frequency) or from a superluminescent source is directed through an optical fiber, in this scenario, the basic task of this emitted light is to experience indirect changes of its parameters whatever in the fiber or in several or in one fiber Bragg gratings, and then get back to a detector which actually measures these changes (Fidanboylu & Efendioglu, 2009). Basic Principles of Fiber Optic Sensors Figure1 demonstrates the standard building of an optical fiber sensor system. As demonstrated in the figure, this system is composed of various elements which work together to complete the system. In this scenario, first component is an optical source (which can be either a LED or Laser diode or laser), sensing or modulator element (which transfers the measure to an optical signal), optical fiber and an optical detector and processing electronics (optical spectrum analyzer and oscilloscope) (Fidanboylu & Efendioglu, 2009). Figure 1Basic Components of a Fiber Sensing system, Image Source: (Fidanboylu & Efendioglu, 2009) Figure 2 Sensing mechanism, Image Source: (Biala, 2001) The working of these sensor is straightforward. Basically, these sensors are responsible for emitting, receiving, and transforming the light energy into an electrical signal. In this entire process, the cable performs the role of a mechanical part that transmits the light out of or into zones that are either too hostile back to the sensor or too space constrained. Additionally, fiber-optic cable is composed of a glass or plastic center that is covered by a coating of cladding matter (as shown in the figure3). Hence, due to the difference between densities of these two elements the cables are able to work in consistent with the phenomena of total internal reflection. Figure 3 Light bounces off the fiber walls of fiber-optic cable, Image Source: (Biala, 2001) Principle of Total Internal Reflection As discussed above, the entire process of light transmission through optical fiber is based on the phenomena of total internal reflection. According to this phenomena all the light that is touching a border between two media will be completely reflected. To be exact, there will be no loss of light energy across the boundary. However, this phenomena works only when two conditions are satisfied: 1. First condition says that the angle of incidence for the specific mixture of materials should be larger than the critical angle. In this scenario, the materials consist of the cladding of the optical fiber and core inside it. 2. The light should move from denser place towards the less dense place. In other words, the source of light should have higher density than the target. In this scenario, cladding material has a lower index of refraction for the reason that cladding material is less dense than the core material. The phenomena of total internal reflection will be valid as long as the above mentioned conditions are met either the fiber-optic cable is straight or turned (Biala, 2001). Types of Sensors with respect to working Bragg Grating Sensors Fiber Bragg gratings are used in the majority of optical fiber sensors. Here, a term is used known as Bragg wavelength, which is the wavelength of extreme reflectivity. Additionally, the majority of optical fiber sensors work on the principle that the Bragg wavelength of a fiber Bragg grating does not only depend on the Bragg grating duration however it also depends on various other parameters such as mechanical strain and temperature (Paschotta2, 2014; Fidanboylu & Efendioglu, 2009). Distributed Sensing There are other techniques of sensing which are not based on fiber Bragg gratings for sensing, but in its place they use the fiber itself. In this scenario, it can change the principle of sensing and it can be based on Raman scattering, Rayleigh scattering or Brillouin scattering. In addition, in many cases, the calculated quantity can be an average over the complete fiber length. Though, this can be a scenario for the specific temperature sensors however it can be the case for Sagnac interferometers which are used as gyroscopes. Moreover, in remaining scenarios, position-dependent parameters such as strained or temperature are calculated and this technique is known as distributed sensing (Paschotta2, 2014; Fidanboylu & Efendioglu, 2009). Quasi-distributed Sensing There is another sensing technique that is known as quasi-distributed sensing, in which a single fiber can have a number of grating sensors in chain with the purpose of monitoring the strain and temperature distribution all through the entire fiber. There is another sensing technique, which makes use of similar weakly reflecting gratings, interrogated with short light pulses, this technique is known as time division multiplexing (TDM). In this scenario, the distinction between different grating reflections is made on the basis of their entrance times. In addition, sometimes wavelength division multiplexing is combined with time division multiplexing with the purpose of multiplying the number of diverse channels to hundreds or even thousands. A user can use switch to choose among different fiber lines, additional multiplying the potential number of sensors (Paschotta2, 2014; Fidanboylu & Efendioglu, 2009). Other Approaches There are many other approaches as well such as Fiber Bragg gratings can be used for interferometric fiber sensors. In this scenario, where they perform the role of reflectors, as well as the determined point transfers outcomes from fiber spans between them. There are also many other sensing technique for instance a sensing technique uses pairs of Bragg gratings as fiber Fabry–Perot interferometers. Basically, Fabry–Perot interferometers respond mainly to outside influences. In addition, various other mechanisms can also be combined with the Fabry–Perot interferometer for instance with a variable air gap in the fiber. Moreover, multi-parameter sensing such as strain and temperature use long-period fiber gratings, as well as alternatively for sensing strain with very little sensitivity to changes in temperature (Paschotta2, 2014; Fidanboylu & Efendioglu, 2009). Applications of Optical Fiber Sensors Though, optical fiber sensors provide a large number of advantages which are comparable to other sensors but after many years of development, they have still not achieved considerable marketable accomplishment. The reasons behind its less attractiveness can be that it is hard to change already working technologies with optical fiber sensors. Even if industries face some limitations with existing technologies. However, fiber-optic sensors are progressively acknowledged as a technology with very stimulating options some application areas. The use of these sensors is highly appreciated for harsh environments, for instance they are heavily used in sensing in high-power machinery and high-voltage, or in microwave ovens (Paschotta2, 2014; Fidanboylu & Efendioglu, 2009). In addition, a large number of industries are already making use of Bragg grating sensors to look into the environments such as in wind turbines, within the wings of airplanes, bridges, oil wells, pipelines and large dams. Moreover, optical fiber sensors are also used in buildings and these building are acknowledged as “smart structures”. These building let one to keep an eye on the internal environment and get significant information on the strain to which different components of the construction are subject, on vibrations, aging phenomena and so on. So these smart structures are believed to be a truly main drivers for the development of optical fiber sensors. Smart structures are a main driver for the further development of fiber-optic sensors (Paschotta2, 2014). In addition, the uses and applications of optical fiber sensors are not limited to above mentioned area. In fact, they are being used in different fields for different purposes. For instance, they are widely used for the measurement of physical characteristics like that displacement, strain, pressure, temperature, velocity, and acceleration in structures of any size or shape (Fidanboylu & Efendioglu, 2009). Advantages in comparison with other sensors As compared to other sensors, optical fiber sensors provides more advantages. Some of the major advantages of optical fiber sensors are outlined below (Biala, 2001; Fidanboylu & Efendioglu, 2009; Paschotta2, 2014): In view of the fact that fiber optical sensors are composed of electrically insulating materials (hence they do not require any electric cables), in this scenario, they can be an excellent choice for use in high-voltage environments. Since these sensors do not involve the electrical sparks, even in the case of flaws. This characteristic makes them an excellent choice to be used in explosive environments, Though, optical fiber sensors do not themselves electrically disrupt other devices however they are immune to electromagnetic interference (EMI), even to adjacent lightning strikes. In view of the fact that these sensors contain chemically passive materials so they do not pollute their environments as well as are not dependent on decomposition. Their operating temperature ranges vary from situation to situation however they are much wider than is possible for a large number of electronic devices. Optical fiber sensors have multiplexing abilities for instance many sensors can be interrogated in a single fiber line with a single optical source. The future of optical fiber sensors Though, the optical fiber sensors are a new area which is developing with the passage of time however its applications are increasing day by day. The researchers from different domains are trying to find ways to make use of these sensors in different areas. For instance, in areas of photonics, researchers putting considerable efforts on turning modern technologies into the instrumentation and sensing framework. Additionally, fiber technology also provides an excellent support for high-power lasers especially advanced nonlinear classification of materials. Hence, it is believed that the fiber taper will re-emerge as a probe to observe the properties of structures on the microscopic, or even nanoscopic scale. In addition, latest developments and advancements in computing and the improved accessibility to prolonged data-handling competency will be useful in improving our capability to understand data from huge arrays of related sensors which can lead towards the development of valuable combinations of balancing sensors. Overall, the exploitation of optical fiber sensor technology will always expand, gradually but progressively (Culshaw, 2005). Conclusion This paper has presented a detailed analysis of optical fiber sensors. This paper has discussed various aspects associated with optical fiber sensors. It basically started with an introduction of the technology and discussed its basic principles and working process. This paper has discussed various uses and applications of optical fiber sensors. The applications of optical fiber sensors are increasing with the passage of time. The researchers are working on its applications in different domains so that these sensors could be combined with other technologies. So it can be concluded that the future of optical fiber sensors is bright. References Biala, N., 2001. An Introduction to Fiber-Optic Sensors. [Online] Available at: http://www.sensorsmag.com/sensors/machine-vision/an-introduction-fiber-optic-sensors-1075 [Accessed 19 February 2014]. Culshaw, B., 2005. Fiber-Optic Sensors: Applications and Advances, Glasgow, Scotland.: University of Strathclyde. EZ, 2014. POF Characteristics and Applications. [Online] Available at: https://sites.google.com/a/electronicbricks.it/electronicbricks/technolgies-and-competitive-advantages/competitive-advantages-of-pof [Accessed 20 February 2014]. Fidanboylu, K. & Efendioglu, H. S., 2009. FIBER OPTIC SENSORS AND THEIR APPLICATIONS. Karabuk, Turkey, 5th International Advanced Technologies Symposium (IATS’09). Industrial Fiber Optics, 2014. Plastic Optical Fiber (POF) Basics. [Online] Available at: http://i-fiberoptics.com/basics.php [Accessed 20 February 2014]. Jasenek, J., 2010. 1. A brief overview and classification of the fiber optic sensors. [Online] Available at: http://www.eaeeie.org/theiere_bratislava/1.html [Accessed 18 February 2014]. Paschotta2, R., 2014. Fiber-optic Sensors. [Online] Available at: http://www.rp-photonics.com/fiber_optic_sensors.html [Accessed 20 February 2013]. Paschotta, R., 2014. Plastic Optical Fibers. [Online] Available at: http://www.rp-photonics.com/plastic_optical_fibers.html [Accessed 22 February 2014]. Polishuk, P., 2006. Plastic Optical Fibers Branch Out, s.l.: IGI Consulting, Inc.. The FOA, 2008. The Fiber Optic Association - Tech Topics. [Online] Available at: http://www.thefoa.org/tech/pof.htm [Accessed 20 February 2014]. Zubia, J. & Arrue, J., 2001. Plastic Optical Fibers: An Introduction to Their Technological Processes and Applications. Optical Fiber Technology, Volume 7, pp. 101-140. Read More