Optical Sensor Using ExpEyes Junior Kit Trilochan Patra Assistant Professor, Electronics and Communication Engineering Techno India College of Technology Newtown, Megacity, Rajarhat, kol-156, W.B, India Abstract: Fiber optic sensor technology offers the possibility of sensing different parameters like strain, temperature and pressure in harsh environment and remote locations. These kinds of sensors modulate some features of the light wave such as intensity, phase and wavelength in an optical fiber or use optical fiber as a medium for transmitting the measurement information. The advantages of fiber optic sensors in contrast to conventional electrical ones make them popular in different applications and now a day they consider as a key component in improving industrial processes, quality control systems, medical diagnostics, and preventing and controlling general process abnormalities. In this paper we represent a displacement sensor by performing an experiment using expEYES junior kit. I. INTRODUCTION Over the past twenty years two major product revolutions have taken place due to the growth of the optoelectronics and fibre optic communications industries. The optoelectronics industry has brought about such products as compact disc players, bar code scanners and laser pointers. The fibre optic communication industry has literally revolutionized the telecommunication industry by providing higher performance, more reliable telecommunication links with ever decreasing bandwidth cost. This revolution is bringing about the benefits of high volume production to component users and a true information superhighway built of glass. In parallel with these developments fibre optic sensor [1-6] technology has been a major user of technology associated with the optoelectronic and fibre optic communication industry. Many of the components associated with these industries were often developed for fibre optic sensor applications. Fibre optic sensor technology in turn has often been driven by the development and subsequent mass production of components to support these industries. As component prices have fallen and quality improvements have been made, the ability of fibre optic sensors to displace traditional sensors for rotation, acceleration, electric and magnetic field measurement, temperature, pressure, acoustics, vibration, linear and angular position, strain, humidity, viscosity, chemical measurements and a host of other sensor applications, has been enhanced. The technology and applications of optical fibers have progressed very rapidly in recent years. Optical fiber, being a physical medium, is subjected to perturbation of one kind or the other at all times. It therefore experiences geometrical (size, shape) and optical (refractive index, mode conversion) changes to a larger or lesser extent depending upon the nature and the magnitude of the perturbation. In communication applications one tries to minimize such effects so that signal transmission and reception is reliable. On the other hand in fiber optic sensing, the response to external influence is deliberately enhanced so that the resulting change in optical radiation can be used as a measure of the external perturbation. In communication, the signal passing through a fiber is already modulated, while in sensing the fiber acts as a modulator. It also serves as a transducer and converts the parameters like temperature, stress, strain, rotation or electric and magnetic currents into a corresponding change in the optical radiation. Since light is characterized by amplitude (intensity), phase, frequency and polarization, any one or more of these parameters may undergo a change. The usefulness of the fiber optic sensor therefore depends upon the magnitude of this change and our ability to measure and quantify the same reliably and accurately. Optical fiber-based sensor technology offers the possibility of developing a variety of physical sensors for a wide range of physical parameters. Compared to conventional transducers; optical fiber sensors show very high performances in their response to many physical parameters such as displacement, pressure, temperature and electric field. Recently, high precision fiber displacement sensors have received significant attention for applications ranging from industrial to medical fields that include reverse engineering and micro-assembly (Laurence et al., 1998; Shimamoto & Tanaka, 2001); Spooncer et al., 1992; Murphy et al., 1991). This is attributed to their inherent advantages such as simplicity, small size, mobility, wide frequency capability, extremely low detection limit and non-contact properties. One of the interesting and important methods of displacement measurement is based on interferometer technique (Bergamin et al., 1993). However, this technique is quite complicated although it can provide very good sensitivity. Alternatively, an intensity modulation technique can be used in conjunction with a multimode fiber as the probe. The multimode fiber probes are preferred because of their International Journal of Innovations in Engineering and Technology (IJIET) Vol. 3 Issue 2 December 2013 157 ISSN: 2319 – 1058