Schrodinger Equation With Spatially and Temporally Random Potential: The Effects of Cross-Phase Modulation in Optical Communication

  • Green A.
  • Littlewood P.
  • Mitra P.
  • Wegener L.

We model the effects of cross-phase modulation in frequency/wavelength division multiplexed optical communications systems, using a Schrodinger equation with spatialy and temporally random potential. Green's funcitons for the propagation of light in this system are calculated using feynman path-integral and diagrammatic techniques. This propagation leads to a non-Gaussian joint distribution ...

Exploratory Analysis of Point Proximity in Subspaces

  • Ho T.

We consider clustering as computation of a structure of proximity relationships within a data set in a feature space or its subspaces. We propose a data structure to represent such relationships, and show that, despite unavoidable arbitrariness in the clustering algorithms, constructive uses of their results can be made by ...

Large Deviation Asymptotics for Occupancy Problems

  • Dupuis P.
  • Nuzman C.
  • Whiting P.

In the standard formulation of the occupancy problem one considers the distribution of r balls in n cells, with each ball assigned independently to a given cell with probability 1/n. Although closed form expressions can be given for the distribution of various interesting quantities (such as the fraction of cells ...

MIMO Capacity Through Correlated Channels in the Presence of Correlated Interferers and Noise: A (not so) Large N Analysis

  • Moustakas A.
  • Sengupta A.
  • Simon S.

The use of multi-antenna arrays in both transmission and reception promises huge increases in the throughput of wireless communication systems. It is therefore important to analyze the capacities of such systems in realistic situations, including correlated channels and correlated noise, as well as correlated interferers with known channel. Here we ...

Dislocation and morphology control during molecular beam epitaxy of AlGaN/GaN heterostructures directly on sapphire substrates

  • Chu S.
  • Hsu J.
  • Manfra M.
  • Pfeiffer L.
  • Weimann N.
  • West K.

We report on the growth and transport characteristics of high- density (~ 1013cm-2) two-dimensional electron gases confined at the AlGaN/GaN interface grown by plasma-assisted molecular- beam epitaxy on sapphire substrates. For structures consisting of a 25nm Al0.30Ga0.70N barrier deposited on a 2m insulating GaN buffer, room temperature mobilities averaging 1400cm2/Vs ...

Embedding k-Outerplanar Graphs into l (sub 1)

  • Chekuri C.
  • Gupta A.
  • Newman I.
  • Rabinovich Y.
  • Sinclair A.

We show that the shortest-path metric of any k-outer planar graph, for any fixed k, can be approximated by a probability distribution over tree metrics with constant distortion, and hence also embedded into l1 with constant distortion. These graphs play a central role in polynomial time approximation schemes for many ...

Artificial Charge-Modulation in Atomic-Scale Perovskite Titanate Superlattices

  • Grazul J.
  • Hwang H.
  • Muller D.
  • Ohtomo A.

The nature and length scales of charge screening in complex oxides is fundamental to a wide range of systems, spanning ceramic varistors, oxide tunnel junctions, and charge-ordering in mixed valence compounds. There are wide variations in the degree of charge disproportionation, length scale, and orientation in these latter configurations, but ...

Sliding density-wave in Sr14Cu24O41 ladder compounds

  • Blumberg G.
  • Dennis B.
  • Eisaki H.
  • Gozar A.
  • Littlewood P.
  • Motoyama N.
  • Uchida S.

Sr14Cu24O41 ladder compounds contain linear fragments of copper oxide planes that are responsible for high-temperature superconductivity in two-dimensional cuprates. The undoped spin 1/2 two-leg ladders have short-range magnetic order and a spin gap in contrast to the two-dimensional antiferromagnetic cuprates. Holes doped into these ladders pair and superconduct at high ...

Spin Dynamics of Sr14Cu24O41 Two-Leg Ladder Studied by Raman Spectroscopy

  • Blumberg G.
  • Dennis B.
  • Eisaki H.
  • Gozar A.
  • Motoyama N.
  • Shastry B.
  • Uchida S.

The two-magnon (2M) excitation at 3000 cm21 in Sr14Cu24O41 two-leg ladder is studied by Raman scattering. A slight anisotropy of the superexchange coupling JXXJk X 0.8 with Jk X 110 6 20 meV is proposed from the analysis of the magnetic scattering. The resonant coupling across the charge transfer gap ...

Antiferromagnetism in CaCu3Ti4O12 studied by magnetic Raman spectroscopy

  • Blumberg G.
  • Dennis B.
  • Gozar A.
  • Koitzsch A.
  • Ramirez A.
  • Trebst S.
  • Wakimoto S.

For CaCu3Ti4O12—an insulator that exhibits a giant dielectric response above 100 K—Cu21 antiferromagnetic spin ordering has been investigated by magnetic Raman scattering and magnetization measurements. Below the Ne´el temperature, TN525 K, magnetic excitations have been identified. Above TN Raman spectra reveal short-range antiferromagnetic fluctuations that increase with cooling like T21. ...

Long-Term Wavelength Switching Measurements with Random Schedules on Fast Tunable Lasers

  • Bhardwaj A.
  • Gripp J.
  • Simsarian J.
  • Zirngibl M.

We demonstrate 26 hours of error-free wavelength switching in less than 50 ns between 32 ITU channels with 100 GHz spacing using a GCSR laser. This corresponds to a packet-loss rate of less than 2*10-11. We also examine the effect of different switching schedules, an important issue for commercial switch ...

Spectral Monitoring of OSNR in High-Speed Networks

  • Agarwal A.
  • Buhl L.
  • Chandrasekhar S.
  • Kilper D.
  • Maywar D.

The conditions under which the optical spectrum can be used for performance monitoring of the OSNR are determined for 10 and 40 Gb/s networks with high spectral efficiency and optical add-drop multiplexers

INFLUENCE OF OPTICAL FILTERING ON RETURN-TO-ZERO DIFFERENTIAL PHASE SHIFT KEYING (RZ-DPSK)

  • Chandrasekhar S.
  • Winzer P.

Simulations and measurements at 40Gbit/s show that RZ-DPSK is more robust to narrow-band optical filtering than on/off keying (OOK), in particular if balanced DPSK detection is employed.

Interfacial Chemistries for Nanoscale Transfer Printing

  • Baldwin K.
  • Loo Y.
  • Rogers J.
  • Willett R.

We have devised a contact printing technique for transferring functional materials from the raised regions of a stamp onto a substrate. The process relies on using self-assembled monolayers as “glues” and “release layers” for pattern transfer. This technique is purely additive and it readily prints nanometer length scale features. Furthermore, ...

MITIGATION OF HIGHER ORDER PMD BY DISTRIBUTING PMD COMPENSATORS IN THE TRANSMISSION LINE

  • Xie C.

The performance of distributed PMD compensation in the transmission line is evaluated, and it is shown that the tolerable PMD increases almost linearly with the number of PMD compensators distributed in the transmission line.

Generation of Low-frequency Components Due to Phase-amplitude Modulation of Subcycle Far-infrared Pulses in Near-field Diffraction

  • Mitrofanov O.
  • Pfeiffer L.
  • West K.

We observe carrier phase dependent generation of low-frequency spectral components in the near-field zone of a subwavelength aperture illuminated by subcycle far-infrared (terahertz) pulses. Diffraction induced II/2-phase shift of the pulse carrier results in the spectral intensity variation of the low-frequency components. The effect demonstrates that spectral content of subcycle ...

Route Oscillations in I-BGP with Route Reflection

  • Basu A.
  • Ong C.
  • Rasala A.
  • Shepherd F.
  • Wilfong G.

We study the route oscillation problem~cite{MGW00,Cis00} in the Internal Border Gateway Protocol (I-BGP)~cite{RL95} when route reflection is used. We propose a formal model of I-BGP and use it to show that even deciding whether an I-BGP configuration with route reflection can converge is an NP-Complete problem. Finally, we propose a ...

Performance Analysis of Call Assignment and Carrier Packing Schemes for TDMA Systems

  • Budka K.
  • Kaufman J.
  • Kodialam M.
  • Sampath A.

In IS-136 and GSM TDMA systems that employ dynamic channel allocation, it is important to minimize the number of active carriers for a given load. This memorandum studies the carrier packing properties of both call assignment and carrier repacking schemes, where the average number of active carriers and the average ...

A Formal Approach for Passive Testing of Protocol Data Portions

  • Chen D.
  • Hao R.
  • Lee D.
  • Miller R.
  • Wu J.
  • Yin X.

Passive testing is a process of detecting faults in a system under test by observing its input/output behaviors only without interrupting its normal operations and proves to be a promising method in network fault management. We study passive testing of data portions of network protocols. We present two algorithms using ...

Time-lens timing-jitter compensator in ultra-long haul DWDM dispersion managed soliton transmissions

  • Mollenauer L.
  • Xu C.

Abstract: A time lens based on clock-driven phase modulators followed by linear dispersion accurately removes timing-jitter. When used prior to the receiver, the time lens greatly improves bit-error-rate performance in DWDM dispersion managed soliton transmissions. Ó2002 Optical Society of America OCIS codes: (060.0060) Fiber-optics and optical communications