Grid Job Routing Algorithms - Phosphorus

Grid Job Routing Algorithmsσ= 2 ξ R b( i)P P(10)2 2XT pol λ ave XTwhere ξ pol is the polarization mismatch factor between the signal and the crosstalk lightwaves.Filter Concatenation (FC)A serious signal impairment that is unique to all-optical networks is distortion-induced eye closure, an effect thatis produced by signal passage through multiple WDM filters between the source and the receiver and originatesmainly from spectral clipping due to the narrowing of the overall filter pass-band [Tomkos01]. This effect isessentially relatively small in a point-to-point optical system since a given signal passes through at most twofilters: a MUX and a DMUX.However, in a transparent optical network, a signal may be demultiplexed and remultiplexed at many networkelements throughout its path before it is finally received. Thus the signal experiences the concatenation of theentire set of filters in its path. The effective spectral transfer function of the filter set is the multiplication of eachof the individual filters’ transfer function, and can therefore be much narrower in spectral width than that of asingle filter [Antoniades02]. This in turn can lead to a time-domain distortion and a distortion-induced eyeclosure penalty that is related to Q penalty.Polarization Mode Dispersion (PMD)Polarization Mode Dispersion is the most important polarization effect for high capacity, long haul systems withhigh bit rates. PMD arises from the birefringence in the fiber that gives rise to the differential group delaybetween the two principal states of polarization. PMD is manifest as a time varying and statistical pulsebroadening and pulse distortion because the perturbation of the fiber symmetry that gives rise to thebirefringence varies randomly in orientation along the fiber and is also dependent on environmental variations,particularly temperature. Because of the statistical nature of PMD, the differential group delay increases withthe square root of the length of the fiber and is expressed in units of ps / km . The penalty induced by thePMD is model using [Cantrell03]:2Q 10.2. B D LPMDPMD= in dB (11)where D PMD is the fiber dispersion parameter (0.5 or 0.1 ps /the length of the transmission fiber and B is the signal bit rate.km for old and new fibers respectively) , L isAlso an upper bound on the maximum lengths of an M-link segment can be defined byfM2∑ ( DPMD,l) dl