**Part 2**

**Photonic Crystals and Applications** 

60 Photonic Crystals – Introduction, Applications and Theory

routing, mode converting). However, this formalism could be extended to different type of functions, such as sensing, in which the inputs are given and the output changes are monitored. In this chapter, dichroic and trichroic RGWN color routing was demonstrated as a proof of concept; however, incorporating more components into the RGWN and therefore increasing the possible degrees of freedom, could allow for more complex devices or alternatively for devices with enhanced performance. Furthermore, we exemplified the RGWN design paradigm using plasmonics, nesting a split element simply by intersecting waveguides, still the concept is broad and implementing the concept using photonic component could open new opportunities in the design of photonic circuitry devices.

This work was supported by the DOE 'Light-Material Interactions in Energy Conversion' Energy Frontier Research Center under grant DE-SC0001293 and by the National Science

Bozhevolnyi, S.I. (2006), Volkov, V.S., Devaux, E., Laluet J.Y., Ebbesen, T.W. Channel

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Foundation under the Graduate Research Fellowship Program.

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**9. Acknowledgements** 

**10. References** 

**4** 

*India* 

**Optical Logic Devices Based** 

Kabilan Arunachalam1 and Susan Christina Xavier2 *1Chettinad College of Engineering and Technology, Karur 2Mookambigai College of Engineering, Pudukkottai* 

Optical components that permit the miniaturization of photonic integrated circuits to a scale comparable to the wavelength of light are good candidates for future optical network and optical computing. All-optical communication is one of the solution for the electronic bottleneck viz speed and size, thanks to their ability to process the information at the speed of light. Optical logic gates are the fundamental components in optical digital information processing. In recent years, researchers have demonstrated all-optical logic gates using different schemes based on nonlinear effects in optical fibers (Ahn et al., 1997; Bogoni et al., 2005; Menezes et al., 2007), in semiconductor devices (Kyoung Sun Choi et al., 2010; Kim et al., 2002; Zhihong Li & Guifang Li 2006; Dorren et al., 2004; Stubkjaer, 2000) and in waveguides (Tetsuro Yabu et al., 2002; Yaw-Dong Wu, 2005; Yaw-Dong Wu et al., 2008). But most of the reported works suffer from certain fundamental limitations including big size,

Nowadays, photonic crystals (PhC) draw significant attention as a platform on which to build devices with dimensions in the order of wavelengths of light for future photonic integrated circuits. They are having some unique properties such as compactness, high speed, low power consumption, better confinement which make them promising candidate in photonic integrated circuits (Yablonovitch, 2003; Cuesta-Soto et al., 2004). Logic functions based on photonic crystal can be realized by nonlinear effect (Notomi et al., 2007), ring resonator (Andalib & Granpayeh, 2009), and multimode interference (Hong-Seung Kim et al 2010). They require significant amount of power, nonlinear material, long interaction length and two different wavelengths for probing and input signals. One of the effects of complex spatial dispersion property in PhC namely self collimation provides a mechanism to employ

Photonic crystals (PhC) are new class of optical material represented by natural or artificial structure with periodic modulation of the permittivity. Multiple interference of light on a periodic lattice leads to a photonic band gap and anomalous dispersion because light with a wavelength close to the period of modulation cannot propagate in certain directions. This

optical switching and logic functions (Zhang et al., 2007; Susan et al., 2010).

low speed and difficult to perform chip-scale integration.

**2. Theory of photonic crystal** 

**1. Introduction** 

**on Photonic Crystal** 
