Investigating Opto-Electronic Properties of Surface Plasmon Structure for Spectroscopic Applications

This chapter is proposed with an approach to analyze reflectance as a function of negative index material thickness for different parameters under the surface plasmon condition and extended approach towards the field enhancement of electric field as function of incidence angle and transmittance as function of incidence angle has been analyzed. This chapter can reflect the good comparison between 3 layer medium and n layer medium model. Characteristic impedance of MIM surface plasmon structure is analytically calculated considering the effect of both Faraday inductance and kinetic inductance. Effect of metal layer thickness, insulator thickness, and electron density are tailored to observe the impedance variation with frequency. Wavelength dependence of characteristic impedance and quality factor of MIM (metal-insulator-metal) surface plasmon structure is analyzed. Structural parameters and damping ratio of the structure is tuned within allowable limit to analyze the variation after detailed analytical computation.

Applications of a Birefringent Lens as an Optical Image Processing Device

A uniaxial birefringent crystal lens with its optic axis perpendicular to the system axis and sandwiched between two properly oriented linear polarizers behaves as an isotropic lens with a radially varying complex mask on its pupil plane. The proposed system may be adapted for both apodization and enhanced resolution just by rotating one of the two linear polarizers even when it is illuminated with a polychromatic source of light. Hence, the system may find applications in the fields of spectroscopy and astronomy. In general, it behaves as a double focus lens. However, by varying the birefringent lens parameters, it is possible to obtain a noticeably large depth-of-focus compared to an identical isotropic lens. An optical imaging system with large depth-of-focus is a prerequisite for many fields of applications particularly for microscope imagery, medical imaging, as well as for automatic inspection in microelectronics industry.

All-Optical Switching and Logic-Gates Design Using Mode (Polarization)-Conversion in Micro-Ring Resonator

The realization of all-optical polarization switch and all-optical logic gates based on polarization-conversion on single silicon micro-ring resonator (MRR) is demonstrated. By adjusting the mode state of the input source as well as the pump light, the all-optical polarization switch, and hence, all-optical NOT, OR/NOR. AND-NAND logic gates are realized. The design is ultra-compact, ultrafast, and less optical power is required for all-optical polarization-conversion-based switch and logic gates, respectively. The MRR also shows outstanding performance as its Q (quality) factor is very high. The design is robust, simple, stable, easy-to-fabricate, and silicon-on-insulator (SOI) compatible. The structure is compatible for interconnects and capable for integrating in electronics as well as in plasmonics circuits.

Investigations on the Microstripline-Fed Wide-Slot Antennas for Wideband Applications

Microstrip patch antennas are printed antennas that find suitability because they are lightweight, low volume, thin in profile, dual frequency, and dual polarization operation, and compatible with MMIC. The objective of chapter is to exhibit the investigations on the bandwidth enhancement of microstrip antennas with special reference to microstrip-line-fed wide-slot antennas. Performances are realized and validated through experimental studies on the impedance properties by VNA and radiation properties by pattern measurement setup. An innovative method for the design of hexagonal wide-slot antenna has been proposed considering it as an equivalent magnetic surface of monopole antenna. Impedance bandwidth of the above slot antenna is enhanced through various tuning stubs. In case of forklike tuning stub, the obtained bandwidth is about 900MHz, for hexagonal stub the available bandwidth is 1751MHz. Further improvement in bandwidth is proposed through rotation of hexagonal wide slot, results in wide bandwidth of 5165 MHz covering all the WLAN and WiMAX applications.

Applications of Electromagnetic Bandgap Structure in Microwave Photonics

Microwave photonics is the arena of research in the 21st century due to ever-increasing ultra-large bandwidth and the meticulous availability of data with very low cost. In this context, conventional optoelectronic devices are replaced by novel photonic counterparts, both in transreceiver design as well as devices and systems. The major objective of this replacement is to reduce noise by means of lower scattering, where photons are only responsible for propagation of electromagnetic wave. With introduction of novel materials, low-loss communication system can now be designed at beyond THz range, mainly due to the physical realization of electromagnetic bandgap structure. This chapter is extended towards plasmonics with the intension of making sensors for beyond THz applications.

Design of Spiral Square Patch Antenna for Wireless Communications

The kapton polyimide material is considered to design conformal antenna with spiral square for radio frequency identification (RFID) and wireless local area network (WLAN) applications. In this chapter, the analysis and investigation has been carried out with spiral square techniques using coplanar waveguide (CPW) feed. The proposed antenna operates at 5.8 GHz with impedance bandwidth of 170 MHz (5.73 - 5.9 GHz) with return loss -25.6 dB and gain is 2.4 dBi. The proposed antenna has considered with different bending angles for investigating the conformal characteristics due to flexibility of the material. These results are presented for omni-directional radiation patterns.

Microstrip Antenna

The microstrip antenna (MSA) consists of a dielectric substrate in between a metallic conducting patch and a ground plane. The most common forms of the MSA are the rectangular and circular patch MSAs. There are several microstrip antenna analysis methods. The most popular models are transmission-line model, cavity model, method of moments, FDTD method, and finite element method. The transmission-line model is the simplest of these methods, and it provides good physical insight but is less accurate. The cavity model is more accurate compared to the transmission-line model, but cavity model is more complex. Though cavity model gives good physical insight, it is rather difficult to model coupling. The full-wave models (which include primarily integral equations/moment method) are very accurate, very versatile, but they are the most complex models and usually give less physical insight. This chapter explores the microstrip antenna.

Optical Switching in Next-Generation Data Centers

The leading content provider companies like Google, Yahoo, and Amazon installed mega-data centers that contain hundreds of thousands of servers in very large scale. The current data center systems are organized in the form of the hierarchal tree structure based on bandwidth-limited electronic switches. Modern data center systems face a number of issues like high power consumption, limited bandwidth availability, server connectivity, energy and cost efficiency, traffic complexity, etc. One of the most feasible solution of these issues is the use of optical switching technologies in the core of data center systems. In this chapter a brief description about the modern data center system is presented, and some prominent optical packet switch architectures are also presented in this chapter with their pros and cons.

Simulative Approach to Realize All Optical-Frequency-Encoded Dibit-Based Integrated Logic Gates

Optics is considered a potential candidate for the realization of logic devices, digital optical systems for communication, and computation exploiting its super-fast speed. Optical logic gates also can act on the basis of frequency conversion process of some nonlinear materials. Further, in this chapter, the authors have mentioned the dibit representation technique for reducing bit error problem at the input and output terminals of all optical digital logic circuits and a control input for selecting particular logic operation. Here the authors have proposed frequency encoded all optical dibit-based integrated AND and OR logic gates with control input, where a single circuit acts as both AND logic gate and OR logic gate using the optical switches like reflected semiconductor optical amplifier and add/drop multiplexer.

Transmission Line and Its Implementation

In unbounded media, wave propagation is supposed to be unguided. The existence of uniform plane wave is considered to be all through the space. Electromagnetic energy related with the wave stretched over a broad area. In TV and radio broadcasting, unbounded medium propagation of the wave is required. Here transmission of information is destined for one and all who may be interested. Another way of transmitting information is by guided media. Guided media acts to direct the transmission of energy from transmitter to receiver. Transmission lines are usually used in low frequency power distribution and in high frequency communications as well as in the ethernet and internet in computer networks. Two or more parallel conductors may be used to construct a transmission line, which connects source to a load. Typical transmission lines consist of coaxial line, waveguide, microstrip line, coplanar waveguide, etc. In this chapter, problems related with transmission lines are solved with the help of EM field theory and electric circuit theory.