**5. Conclusions**

14 Optical Amplifier

*SS-SSPN SS-SSPW SS-ASPN SS-ASPW*

*N=*16 *Nsyn*=4 *B*=40Gb/s *PLP*=10-6

0,1 0,15 0,2 0,25 0,3 0,35 0,4 0,45 0,5 0,55 0,6

**Offered Traffic (***p***)**

4 8 12 16 20 24 28 32 36 40 44 48 52 56 60 64

*SS-ASPN (p=0,2) MS-ASPN (p=0,2) SS-ASPN (p=0,4) MS-ASPN (p=0,4) SS-ASPN (p=0,6) MS-ASPN (p=0,6) SS-ASPN (p=0,8) MS-ASPN (p=0,8)*

*M=64 B*=40Gb/s

**Number of Input/Output Fibers (***N***)**

Fig. 13. Comparison of average energy consumption per bit in Single Stage (SS) SSPN and Benes (B) SSPN switches versus the number *N* of Input/Output Fibers for *M*=6 and *p* varying from 0,2 to 0,8. The turned off SOAs are polarized with a current *ioff*=7mA.

Fig. 12. Average energy consumption per bit in Single Stage(SS) ASPW, ASPN, SSPW and

wavelengths and the number of WCs are dimensioned so that the the PLP is smaller than or

SSPN switches versus the offered traffic for *N*=16 and *NSYN*=4. The number *M* of

0,00E+00

1,00E-02

1,00E-01

**Energy Consumption per bit (nJ/bit)** 

1,00E+00

1,00E-02

2,00E-02

**Energy Consumption per bit (nJ/bit)**

equal to 10−6.

3,00E-02

4,00E-02

The chapter discussed issues concerning power consumption of future high-capacity optical packet nodes. When using optical buffers, due to attenuation problems, optical nodes consumes more power than electronic nodes. For this reason we have taken into account bufferless OPS equipped with shared Wavelength Converters to solve output packet contentions. We have proposed some sophisticated analytical models in order to evaluate and compare the power consumption in OPSs equipped with Single-Stage and Multi-Stage switching Fabric. The obtained results show that in the case of OPS equipped with Single-Stage switching fabric, the combination of the asynchronous operation with the wavelength-based system partitioning in Asynchronous Shared-Per-Wavelength OPS leads to significant power saving with respect to the other solutions in the range of interest for switching fabric dimensioning. Finally we have also shown that for larger switches, the BENES switch has an energy consumption lower than the one of an Single-Stage switch if the current injection of the turned off SOAs is considered.
