Lattice approach to the dynamics of phase-coded soliton trains

We address the collective dynamics of a soliton train propagating in a medium described by the nonlinear Schrödinger equation. Our approach uses the reduction of train dynamics to the discrete complex Toda chain (CTC) model for the evolution of parameters for each train constituent: such a simplification allows one to carry out an approximate analysis of the dynamics of positions and phases of individual interacting pulses. Here, we employ the CTC model to the problem which has relevance to the field of fibre optics communications where each binary digit of transmitted information is encoded via the phase difference between the two adjacent solitons. Our goal is to elucidate different scenarios of the train distortions and the subsequent information garbling caused solely by the intersoliton interactions. First, we examine how the structure of a given phase pattern affects the initial stage of the train dynamics and explain the general mechanisms for the appearance of unstable collective soliton modes. Then we further discuss the nonlinear regime concentrating on the dependence of the Lax scattering matrix on the input phase distribution; this allows one to classify typical features of the train evolution and determine the distance where the soliton escapes from its slot. In both cases, we demonstrate deep mathematical analogies with the classical theory of crystal lattice dynamics.

Lattice approach to the dynamics of phase-coded soliton trains

We address the collective dynamics of a soliton train propagating in a medium described by the nonlinear Schrödinger equation. Our approach uses the reduction of train dynamics to the discrete complex Toda chain (CTC) model for the evolution of parameters for each train constituent: such a simplification allows one to carry out an approximate analysis of the dynamics of positions and phases of individual interacting pulses. Here, we employ the CTC model to the problem which has relevance to the field of fibre optics communications where each binary digit of transmitted information is encoded via the phase difference between the two adjacent solitons. Our goal is to elucidate different scenarios of the train distortions and the subsequent information garbling caused solely by the intersoliton interactions. First, we examine how the structure of a given phase pattern affects the initial stage of the train dynamics and explain the general mechanisms for the appearance of unstable collective soliton modes. Then we further discuss the nonlinear regime concentrating on the dependence of the Lax scattering matrix on the input phase distribution; this allows one to classify typical features of the train evolution and determine the distance where the soliton escapes from its slot. In both cases, we demonstrate deep mathematical analogies with the classical theory of crystal lattice dynamics.

"Our kith and kin"?:Sri Lankan Tamil refugees and the ethnonationalist parties of Tamil Nadu

This article explains the impact of substate nationalism on the political dynamic surrounding ethnic kin migration through a case study of Sri Lankan Tamil refugees in the southern Indian State of Tamil Nadu. Examples drawn from the migration studies literature identify ethnic kinship between refugees and host as an indicator of favorable reception and assistance. While this expectation is borne out to an extent in the Tamil Nadu case, it is tempered by a period of hostility following the 1991 assassination of former Indian Prime Minister Rajiv Gandhi by an LTTE suicide bomber, when the refugees were figured as a disruptive and dangerous presence by Tamil Nadu's political elites. A version of the "triadic nexus" model of kin state relations, reconfigured to accommodate the larger political unit within which the substate nationalism is incorporated, is proposed as a framework of analysis for these events. This can better account for Tamil Nadu's substate ethnonationalist elite's movement between expressions of coethnic solidarity with the refugees and the more hostile, security-focused response postassassination. © Taylor & Francis Group, LLC.

Sensitivity enhanced SRI sensor based on an Ex-TFG in thin cladding fiber

A high sensitivity SRI sensor was fabricated by inscribing an ex-TFG in a thin cladding fiber, achieving enhanced SRI sensitivities of the TM and TE resonance peaks around 1180nm/RIU and 1150nm/RIU at the index of 1.345. © 2014 OSA.