We propose the analytic solution of cross-spectral density matrix (CSDM) of a partially coherent vortex beam while propagating. The solution to the propagation law is appropriate for a Gaussian Schell-model vortex beam to any order. It is found that the solution of CSDM of a Gaussian Schell-model beam revealed by Emil Wolf is a special instance. By this general solution, the intensity distribution, especially the degree of polarization and the mean-squared beam width of the partially coherent vortex beam, are investigated. It is found that the propagation character of the beam width is decided by the correlation-length, and that the topological charge affects only the value of the beam width.
Based on the theory of Mueller matrix of optical devices with both polarization dependent loss (PDL) and birefringence, the definition of polarization loss (PDL) is analyzed. The newly formulated equations for PDL are generalized for input light with arbitrary degree of polarization (DOP). Theoretical derivation shows that the overall polarization states should contain all the polarization states with random DOP. The magnitude of PDL has connection with the input DOP. The direction of PDL vector is only decided by the Mueller matrix.
A combination of polarization-mode dispersion (PMD) and polarization-dependent loss (PDL) in optical fibers may lead to anomalous pulse broadening. It raises the issue for more complete assessments when studying pulse propagation in the presence of polarization-dependent loss. A mathematical description is put forward in this work, where PMD is evaluated in the presence of XPM, PDL, and chirp. Simulation shows that the delay of a chirped Gaussian pulse depends not only on PDL, but also on the chirp of the pulse itself. To some degree, effective PMD can be controlled by PDL and chirp. The results give guidance for PMD compensation.
We present an analytical model to study the multiclass-traffic-based optical burst switching system. In contrast with the previous on-off burst arrival process model, which is based on a single class of traffic and depends on just one probability of bursts to choose output ports, in our scheme we evaluate the blocking probability for multiclass bursts at the core router, which chooses output ports depending on differential probability, and we give some useful discussion for the design of real optical burst switching networks.
Segment-dividing model is appropriate for research on PMD. Mathematical deduction is made to change it into iterative model. It is easy to find the new model gives clear meaning in physics and reveals the process of PMD accumulation in fiber. It is applicable for being transplanted to analysis on PMD. This iterative method is put forward for practical numeration. When stochastic factor is taken into account on PMD analysis, more elements should be added. Thus statistical mode is put forward. In the statistical mode, the stochastic factor contains two parameters: the mean length of the whole little segments L and the number of the segments N. the choice on the mean length and the number of the segments is a complex problem. Research is done on this problem and results indicate that the choice of L determines the veracity of the statistical model.
Optical burst switching (OBS) network has been proposed as a novel network scheme which can realize IP over WDM and also been regarded as the trend of the next optical generation network. In OBS network, burst contention phenomena may often occur at the output data channel in core routers and the contention can bring on the data losing.
Optical composite burst switching (OCBS) has been regarded as an efficient approach for the resolution scheme in burst contention, which segments and drops the header of contending burst, but OCBS may bring unfairness to burst dropping, this unfairness causes the OBS network can't well support quality of service (QoS). The previous works that focus on the resolution approaches for the unfairness have some limitations and also could bring unfairness to OBS network. An improved resolution approach has been proposed to solve the unfairness of burst segmentation and dropping in optical burst switching multi-hop network in this paper, this approach not only could maintain the advantage of conventional resolution approach, which could make the packets loss probability coherence in
multi-hop network but also could decreases the data losing and increase the throughput for OBS network. At last, some simulations prove the validity of the proposed approach and it has the theoretic meaning to design the real OBS network in practice.