**4. Photonic crystal optical logic devices for a packaged system**

In a complete packaged system, photonic crystal based laser light sources, logic gates and detector are integrated within a single chip. Figure 12 illustrates the integrated photonic crystal based devices. Light source laser is based on a 2D photonic crystal slab patterned with a square lattice. Holes are drilled in GaAs dielectric material. The periodicity of the holes is fixed at 315 nm, and the hole radius is tuned from 105 to 130 nm to change the resonance frequency of the cavities (Hatice Altug et al., 2006). Lasers are driven by the given electrical signals and the corresponding optical output is applied to the all-optical logic gate. Laser 1 & 2 output signals are coupled using coupler and launched to the input port 1 of logic gate and the phase locked reference signal is applied to input port 2. All-optical logic gate performs the logical functions in optical domain.

In the integrated photonic crystal based logic gates, output value of the logic gate will be standardized using a PhC amplifier. The gain of the amplifier is adjusted such that the output level is either "1" or "0". In Figure 12 AND logic gate output is standardized and given to one of the input of XOR gate and other input is getting from the output of another preceding logic gate. Thus the standardized output of one logic gate is given to the input port of the next in sequence logic gate and so on. Finally the output of the last logic gate is applied to the photodetector. The photodetector detects the optical signal. Photo detector is designed using triangular air-hole photonic crystal with lattice constant is 420nm and slab thickness is 204 nm (M Notomi and T Tanabe 2010). The detector converts the optical signal into electrical output.

Optical Logic Devices Based on Photonic Crystal 79

Ahn, K. H.; Cao, X. D. ; Liang, Y.; Barnett, B. C. ; Chaikamnerd, S. & Islam M. N. (1997).

Andalib, P. & Granpayeh,N. (2009). All-optical ultra-compact photonic crystal AND gate

Bogoni, A. ; Pot`,L.; Proietti, R.; Meloni, G. ; Ponzini, F. & Ghelfi, P.(2005). Regenerative and

Chul-Sik Kee; Do-Kyeong Ko; Jongmin Lee; Sun-Goo Lee & Hae Yong Park (2007). Self-

Deyin Zhao; Jie Zhang; Peijun Yao & Xunya Jiang (2007). Photonic crystal Mach-Zehnder

Dorren, H. J. S. ; Xuelin Yang ; Mishra, A.K.; Zhonggui Li ; Heongkyu Ju ; De Waardt, H.;

Hatice Altug ; Dirk Englund and Jelena Vuckovic(2006). Ultrafast photonic crystal

Hong-Seung Kim; Tae-Kyung Lee ; Geum-Yoon Oh ; Doo-Gun Kim & Young-Wan Choi

Igor A. Sukhoivanov & Igo r V. Guryev (2009), Photonic Crystals Physics and Practical Modeling, *Springer Series in optical sciences,* ISBN 978-3-642-02645-4, USA Kim, J.H.; Jhon, Y.M. ; Byun, Y.T. ; Lee, S. ; Woo, D.H. & Kim, S.H. (2002). All-optical XOR

Kosaka, H. ; Kawashima, T. ; Tomita, A.; Notomi, M. ; Sato, T. & Kawakami ,S. (1999) Self-

Kyoung Sun Choi; Young Tae Byun; Seok Lee & Young Min Jhon (2010). All-Optical

Menezes, J. W. M.; Fraga, W. B.; Ferreira, A. C.; Saboia, K. D. A.; Filho, A. F. G. F.;

Cascadability and functionality of all-optical low-birefringent non-linear optical loop mirror: Experimental demonstration, *Journal Optical Society of America B*, Vol.

based on nonlinear ring resonators, *Journal Optical Society of America B*, Vol. 26,

reconfigurable all-optical logic gates for ultra-fast applications, *Electronics Letters*,

Collimated Beams in Two-Dimensional Photonic Crystals: Properties and Applications, *Journal of the Korean Physical Society*, Vol. 51, No. 4, pp. 1479-1483 Cuesta-Soto, F.; Martínez, A.; García, J.; Ramos, F.; Sanchis, P.; Blasco, J. & Martí, J. (2004).

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

interferometer based on self-collimation, *Applied Physics Letter*, Vol. 90, pp. 231114-

Khoe, G.D.; Simoyama, T. ; Ishikawa, H. ; Kawashima, H. & Hasama, T. (2004). All-optical logic based on ultrafast gain and index dynamics in a semiconductor optical amplifier, *IEEE Journal of Selected Topics Quantum Electronics*, Vol. 10, No. 5,

(2010). Analysis of all optical logic gate based on photonic crystals multimode interference, *Proceedings of SPIE,* ISBN 9780819480026, San Francisco, 23-28 January

gate using semiconductor optical amplifiers without additional input beam, *IEEE* 

collimating phenomena in photonic crystals, *Applied Physics Letter.* Vol. 74, pp.

OR/NOR Bi-functional Logic Gate by Using Cross-gain Modulation in semiconductor Optical Amplifiers, *Journal of the Korean Physical Society*, Vol. 56,

Guimarães,G. F.; Sousa, J. R. R.; Rocha, H. H. B.& Sombra, A. S. B.(2007). Logic

**7. References** 

14, No. 5, pp. 1228–1236

Vol. 41, No. 7, pp. 435-436

*Optics Express,* Vol. 12, No. 1 , pp. 161-167

nanocavity laser, Nature Physics, Vol 2, pp. 484-488

*Photonics Technology Letters*, Vol.14, No.10, pp. 1436–1438

No.1, pp. 10-16

231116

2010

1212-1214

No. 4, pp. 1093-1096

pp. 1079–1092

Fig. 12. Integrated photonic crystal based devices
