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ABSTRACT: A general mathematical basis for analyzing propagation of partially coherent light in nonlinear, non-instantaneous, Kerr media is presented. The presentation unifies existing approaches, but also provides the generalizations necessary for an analysis of more complicated wave fields than those previously considered. In particular, it is demonstrated how to generalize the analysis to situations where the light field originates from several sources, which do not necessarily have the same stochastic properties.
Journal of Physics A Mathematical and Theoretical 07/2008; 41(33):335207. · 1.56 Impact Factor
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ABSTRACT: The present work reports on an analytical, numerical, and experimental analysis of the importance of electric field singularities around sharp corners for the determination of the breakdown strength of microwave RF devices. It is shown that only under certain physical circumstances, does the singularity and the concomitant strongly enhanced microwave field determine the breakdown strength. In particular, in situations where diffusion is the dominating loss mechanism for the electron density, it is shown that breakdown is a volumetric process and that the field singularity does not determine the breakdown threshold. Conditions for volumetric and localized breakdown respectively are established analytically and the validity is demonstrated by numerical simulations. Finally an experimental investigation is made which confirms the predicted behavior and demonstrates the accuracy which is possible to obtain for the determination of the breakdown threshold
Microwave Symposium Digest, 2006. IEEE MTT-S International; 07/2006
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ABSTRACT: Based on the Wigner distribution approach, an analysis of the effect of partial incoherence on the transverse instability of soliton structures in nonlinear Kerr media is presented. It is explicitly shown that for a Lorentzian incoherence spectrum the partial incoherence gives rise to a damping which counteracts, and tends to suppress, the transverse instability growth. However, the general picture is more complicated and it is shown that the effect of the partial incoherence depends crucially on the form of the incoherence spectrum. In fact, for spectra with finite rms-width, the partial incoherence may even increase both the growth rate and the range of unstable, transverse wave numbers.
Physical Review E 09/2004; 70(2 Pt 2):026603. · 2.26 Impact Factor
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ABSTRACT: It is shown that the properties of the modulational instability of partially coherent waves propagating in a nonlinear Kerr medium depend crucially on the profile of the incoherent field spectrum. Under certain conditions, the incoherence may even enhance, rather than suppress, the instability. In particular, it is found that the range of modulationally unstable wave numbers does not necessarily decrease monotonically with increasing degree of incoherence and that the modulational instability may still exist even when long wavelength perturbations are stable.
Physical Review E 03/2004; 69(2 Pt 2):025601. · 2.26 Impact Factor
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ABSTRACT: It is shown that the properties of the modulational instability of partially coherent waves propagating in a nonlinear Kerr medium depend crucially on the profile of the incoherent field spectrum. Under certain conditions, the incoherence may even enhance, rather than suppress, the instability. In particular, it is found that the range of modulationally unstable wave numbers does not necessarily decrease monotonously with increasing degree of incoherence and that the modulational instability may still exist even when long wavelength perturbations are stable. Comment: 4 pages, 2 figures, submitted to Phys. Rev. Lett
09/2003;
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ABSTRACT: A detailed theoretical and experimental investigation is made of
the breakdown threshold of air-filled microwave components. The effects
on the breakdown threshold of air pressure, pulse length, and the strong
inhomogeneity of the microwave fields characteristic of resonators are
analyzed. Particular attention is given to the increased liability of
breakdown in multi-carrier as compared to single carrier operation
Microwave Symposium Digest, 1999 IEEE MTT-S International; 02/1999
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ABSTRACT: A theoretical and experimental investigation is made of the leakage power in microwave transmit–receive switches. The peak leakage power is shown to be independent of incident peak power but to depend on the rise time of the incident pulse. The plateau leakage power through the switch is also estimated and shown to be independent of incident peak power. The theoretical predictions for peak leakage power and plateau leakage power are compared and found to be in good agreement with experimental results. © 1996 American Institute of Physics.
Journal of Applied Physics 01/1997; · 2.17 Impact Factor
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ABSTRACT: An analytical and numerical investigation is made of electric
field enhancement due to scattering of an incident plane wave by a
biconical conductor. An application to microwave transmit-receive
switches (TR) shows that field enhancement factors of the order of 20 to
40 are to be expected in the region close to the keep-alive contacts. An
analysis of the microwave absorption by a small plasma sphere located in
the vertex of the biconical conductor is also presented, showing that
the plasma sphere absorbs a significant fraction of the incident power
independently of the plasma size. This explains the observed absorption
properties during the turn-on phase of TR switches
IEEE Transactions on Microwave Theory and Techniques 03/1995; · 1.85 Impact Factor
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ABSTRACT: A detailed analytical investigation is made of the threshold for
breakdown in microwave transmit-receive switches. The geometry of the
keep alive contacts of the switch is modeled as a double cone
configuration, and the subsequent diffusion equation for the electron
density in the presence of strongly inhomogeneous ionization is solved
analytically. Predictions for the breakdown power are found to be in
agreement with previously presented experimental results
IEEE Transactions on Microwave Theory and Techniques 06/1993; · 1.85 Impact Factor
