Publication Date

2015

Journal or Book Title

PHYSICAL REVIEW E

Abstract

We introduce a ladder-shaped chain with each rung carrying a parity-time- (PT -) symmetric gain-loss dimer. The polarity of the dimers is staggered along the chain, meaning alternation of gain-loss and loss-gain rungs. This structure, which can be implemented as an optical waveguide array, is the simplest one which renders the system PT -symmetric in both horizontal and vertical directions. The system is governed by a pair of linearly coupled discrete nonlinear Schrödinger equations with self-focusing or defocusing cubic onsite nonlinearity. Starting from ¨ the analytically tractable anticontinuum limit of uncoupled rungs and using the Newton’s method for continuation of the solutions with the increase of the inter-rung coupling, we construct families of PT -symmetric discrete solitons and identify their stability regions. Waveforms stemming from a single excited rung and double ones are identified. Dynamics of unstable solitons is investigated too.

Comments

Uploaded as published. DOI: 10.1103/PhysRevE.91.033207

Pages

11 pp.

Volume

91

Issue

033207

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