**5. References**


also be employed for design and implementation of the gate. The AlGaAs/GaAs heterostructure can be grown by metal-organic chemical vapor-phase deposition (MOCVD); where a 300 nm silicon oxide is deposited over the wafer using plasma enhanced chemical vapor-phase deposition (PECVD), followed by a 200-nm-thick layer of PMMA as electronbeam resist. The pattern is then transferred into the oxide hard mask via reactive ion etching (RIE) using a fluorine process. The deep etching of the PC holes can be achieved using chemically assisted ion beam etching (CAIBE) in a Chlorine-Argon process (Ayre et al., 2005). The holes would thus be approximately 605nm deep. The input wavelength is assumed 1550nm which can be obtained using an Erbium doped fiber laser which results in

Andalib, P.; Granpayeh, N. (2009). All-optical ultra-compact photonic crystal NOR gate

Ayre, M.; Karle, T. J.; Wu, L.; Davies, T.; Krauss, T. F. (2005) Experimental verification of

Selected Areas in Communications, vol. 23, no. 7 (Jul. 2005) pp. 1390-1395. Bai, J.; Wang, J.; Jiang, J.; Chen, X.; Li, H.; Qiu, Y.; Qiang, Z. (2009). Photonic crystal NOT

Borel, P.I.; Frandsen, L.H.; Harpøth, A.; Kristensen, M.; Jensen, J. S.; Sigmund, O. (2005).

Boyd, R. W. (2003) Nonlinear Optics, Academic Press, San Diego, USA, ISBN: 0121216829. Bravo-Abad, J.; Fan, S.; Johnson, S. G.; Joannopoulos, J. D.; Soljacic´, M. (2007). Modeling

Centeno, E.; Felbacq, D; (2000). Optical bistability in finite-size nonlinear bidimensional

Cuesta-Soto, F; Martinez, A.; Garcia, J.; Ramos, F.; Sanchis, P.; Blasco, J.; Marti, J. (2004).

Cuesta-Soto, F; Martinez, A; Garcia, J; Ramos, F; Sanchis, P; Blasco, J; Marti, J. (2004). All-

Danaie, M.; Attari, A. R.; Mirsalehi, M. M.; Naseh, S. (2008). Design of a high efficiency

Danaie, M.; Kaatuzian, H. (2011). Improvement of power coupling in a nonlinear photonic

Fundamentals and Applications, vol. 6, no. 3-4, (Dec. 2008) pp. 188–193. Danaie, M., Kaatuzian, H. (2011). Bandwidth Improvement for a Photonic Crystal Optical Y-

based on nonlinear ring resonators, J. of Optics A: Pure and Applied Optics, vol. 11,

numerically optimized photonic crystal injector, Y-splitter, and bend, IEEE J.

and NOR gates based on a single compact photonic crystal ring resonator, Applied

Topology optimised broadband photonic crystal Y-splitter, IEE Electron. Let., vol.

nonlinear optical phenomena in nanophotonics, J. of Lightwave Technol., vol. 25,

photonic crystals doped by a microcavity, Phys. Rev. B, Condens. Matter, vol. 62,

All-optical switching structure based on a photonic crystal directional coupler,

optical switching structure based on a photonic crystal directional coupler, Optics

wide-band 60º bend for TE polarization, Photonics and Nanostructures:

splitter, Journal of the Optical Society of Korea, vol. 15, no. 3 (Sep. 2011) pp. 283-

crystal directional coupler switch, Photonics and Nanostructures – Fundamentals

the device size to be approximately equal to 5.95μm×12.90μm.

Optics, vol. 48, no. 36 (Dec. 2009) pp.6923-6927.

no. 8, (Aug. 2009) 08523.

41, no. 2 (Jan. 2005) pp. 69-71.

no. 9, (Sep. 2007) pp. 2539-2546.

no. 12, (Sep. 2000) pp. R7683-R7686.

Optics Express, vol. 12, no. 1, (Jan. 2004) pp. 161-167.

and Applications, vol. 9, no. 1 (Feb. 2011) pp. 70–81.

Express, vol. 12, no. 1, (Dec. 2003) pp. 161-167.

**5. References** 

288.


**9** 

*Bulgaria* 

**Thin Chalcogenide Films for** 

Rossen Todorov, Jordanka Tasseva and Tsvetanka Babeva *Institute of Optical Materials and Technologies "Acad. J. Malinowski"* 

In nature glass is formed as a result of rapid cooling and solidification of rock melts of volcanic origin. That hints at the existence of glass to have dated back since the dawn of creation. Man has quite soon borrowed the pattern to synthesize glass for their needs: in the production of glass beads and glazes for ceramic pots and vases (3500 BC), hollow glass items (1500 BC) - these developing further through the discovery of glassblowing (between 27 BC and AD 14), leading to fabrication of cast glass windows by Romans (around AD 100) and glass sheets (11th century) (http://glassonline.com/infoserv/history.html). Starting its applications as a non-transparent material for decoration purposes, glass has made a breakthrough to become used in a wide range of fields - from housing construction through optics (for lenses and protective coatings for mirrors), information processing (optical fibres and, in general, waveguides) and storage to photonics. The ingredients of the first accidentally man-synthesized glass were nitrate and sand, the latter being mostly composed of silica (SiO2), usually in the form of quartz. On its part, quartz is the second most abundant mineral in the Earth's continental crust and is thus justifiable as a basic material in glassproduction. Its high glass-transition temperature, however, places some limitations for its applications and other substances, such as sodium carbonate, aluminium, boron, calcium, cerium, magnesium, lead, thorium oxides are added to facilitate the processing and modulate the optical properties, e.g. refractive index. Alternatively, there are non-silica containing glasses as: borate, fluoride, phosphate and chalcogenide. Namely "chalcogenides" stay in the scope of the present chapter to be revealed as superb materials for photonics and in particular – photonic crystals (PhC). It would be traced in Section 3 what are the properties that we strive to derive out from chalcogenides in order to conform to the theoretical considerations. In the following lines, however we will see what

The term "chalcogen" – meaning "ore former" (from "*chalcos"* old Greek for "ore") – is a characteristic name that was proposed by Fischer in 1932 to refer to the group of elements O, S, Se, and Te (Fischer, 2001). "Chalcogenides" is used to address chalcogen's compounds with elements such as As (arsenic), Ag (silver), Bi (bismuth), Cu (copper), Cd (cadmium), Fe

**1. Introduction**

chalcogenides originally offer.

**2. Chalcogenide glasses and their properties** 

**Photonic Applications** 

*Bulgarian Academy of Sciences* 

