**7. References**


Asghari M., White I.H., Penty R.V., 'Wavelength conversion using semiconductor optical amplifiers, J.Lightwave Technology, Vol.15, No.17,1997, pp.1181-1190 Awwal A.A.S., Karim M.A.(1990), 'Microprocessor design using polarization encoded optical shadow casting', Appl. Opt., Vol.29, No.14,1990, pp. 2107-2112. Chakraborty B., Mukhopadhyay S.(2009), 'Alternative approach of conducting Phase-

Connelly M.J.(2008), 'Semiconductor Optical Amplifiers', Kluwer Academic Publishers,

Dorren H.J.S., Lenstra D., Liu Y, Hill M. T., Khoe G.D.(2003), 'Nonlinear Polarization

Dutta N.K., Wang Q.(2006), 'Semiconductor Optical Amplifiers', World Scientific

Fatehi M.T., Wasmundt K.C., Collins S.A.(1984), 'Optical flip-flops and sequential logic

Fu S., Zhong W.D., Shum P., Wu C., Zhou J.Q.(2007), 'Nonlinear Polarization rotation in

Garai S.K.(2010), 'A scheme of developing frequency encoded tristate-optical logic

Garai S.K.(2011), 'A method of developing frequency encoded multi-bit optical data

Garai S.K.(2011a), 'Method of all-optical frequency encoded decimal to binary and BCD,

Garai S.K.(2011b), 'A novel method of designing all optical frequency encoded Fredkin and

Garai S.K.(2011c), "A novel all-optical frequency encoded method to develop Arithmetic and

Garai S. K.(2012), 'A novel method of developing all optical trinary JK, D-type and T-type

Garai S. K., Mukhopadhyay S.(2009), 'Method of implementing frequency encoded

Amplifiers', Optics and Laser Technology, ,Vol.41, No.8,2009, pp.972-976 .

Photonics TechnologyLetters,Vol.19, No.23,2007, pp.1931-1933.

amplifiers', Applied Optics, Vol.50, No.21,2011,pp.3795-3807.

Light wave Technology, Vol.29, No.23, 2011, pp. 3506-3514.

modulated all-optical logic gates'', Optical Engineering,Vol. 48, No.3, March 2009,

Rotation in Semiconductor Optical Amplifiers: Theory and Application to All-Optical Flip-FlopMemories", IEEE Journal of Quantum Electronics, Vol.39, No.1,

circuits using a liquid crystal light valve', Appl. Optics, Vol.23, No.13,

semiconductor optical amplifiers with linear polarization maintenance', IEEE

operations using Semiconductor Optical Amplifier', Journal of Modern

comparator using Semiconductor Optical Amplifier', Optics and Laser Technology,

binary to gray' and gray to binary data conversion using semiconductor optical

Toffoli logic gates using semiconductor optical amplifiers', IET Optoelectronics,

Logic Unit (ALU) using semiconductor optical amplifiers," IEEE/OSA Journal of

flip-flops using semiconductor optical amplifiers', Applied Optics, (In Press-

multiplexer and demultiplexer systems using nonlinear Semiconductor Optical

**7. References** 

pp.035201-5.

2003, pp.141-148.

1984,pp.2163-2171.

Publishing, Singapore, 2006(Chapter 8).

Optics,Vol.57, No.6,2010, pp.419-428.

Vol.43, No.1, 2011, pp.124-131.

Vol.5, No.6, 2011, pp.247-254.

20.12.2011)

2002


**0**

**4**

<sup>2</sup>*Co.Ri.Tel. Italy*

**SOA-Based Optical Packet**

V. Eramo1, E. Miucci1, A. Cianfrani1, A. Germoni2 and M. Listanti1

The service evolution and the rapid increase in traffic levels fuel the interest toward switching paradigms enabling the fast allocation of Wavelength Division Multiplexing WDM channels in an on demand fashion with fine granularities (microsecond scales). For this reason, in the last years, different optical switching paradigms have been proposed (Sabella et al., 2000): optical-packet switching (OPS), optical-burst switching (OBS), wavelength-routed OBS, etc. Among the various all-optical switching paradigms, OPS attracts increasing attention. Owing to the high switching rate, Semiconductor Optical Amplifier (SOA) is a key technology to realize Optical Packet Switches. We propose some Optical Packet Switch (OPS) architectures and illustrate their realization in SOA technology. The effectiveness of the technology in reducing the power consumption is also analyzed. The chapter is organized in three sections. The main blocks (Switching Fabric, Wavelength Conversion stage, Synchronization stage) of an OPS are illustrated in Section 2 where we also show some examples of realizing wavelength converters and synchronizers in SOA technology. Section 3 introduces SOA-based single-stage and multi-stage switching fabrics. Finally the SOA-based

The considered optical switch architecture (Eramo, 2000; 2006; Sabella et al., 2000) is shown in Fig. 1. It has *N* input and output fibers, each fiber supports a WDM signal with *M* wavelengths, so an input (or output) channel is characterized by the couple (*i*, *λj*) wherein *i* (*i* ∈ 1, ··· , *N*) identifies the input/output fiber and *λj*, (*j* ∈ 1, ......, *M*) identifies the wavelength. In general, optical packet switches can be divided into two categories: slotted (synchronous) and unslotted (asynchronous) networks. In a synchronous switch (Eramo, 2000), as illustrated in Fig. 1 packets with fixed length are aligned (synchronized) by synchronizers before they enter the switch fabric. This type of switch generally achieves a fairly good throughput since the behavior of the packets is regulated. However, complex and expensive synchronization hardware is needed at each node. On the other hand, in an asynchronous switch (Eramo et al., 2003), the packets are not aligned and they are switched one by one on the fly. Asynchronous networks generally have lower cost, better flexibility, and robustness, but usually they have lower overall throughput than synchronous networks. The switch architecture is equipped with a number *r* of WCs which are shared according

**1. Introduction**

OPS power consumption is investigated in Section 4.

**2. Optical packet switching architectures**

**Switching Architectures**

<sup>1</sup>*DIET Sapienza University of Rome,*

