ABSTRACT Separation of transverse modes in waveguides typically achieved by manipulating mode effective indices is of current interest in integrated optics and various designs have been proposed. Recently, implementation of non-Hermitian optics under parity time (PT) symmetry has led to an alternate class of devices employing gain and loss media with far reaching results. Introduction of PT symmetry to non-Hermitian systems results in real solutions while symmetry breaking results in imaginary eigenvalues. However, applications of PT symmetry in the infrared devices is quite limited. In this work, we demonstrate a mode splitter that can separate transverse modes in coupled PT symmetric in realistic quantum cascade lasers (QC lasers). We study the effects of gain and loss for coupled PT symmetric QC laser waveguides and show that TE0 and TE1 modes can be separated with proper choice of gain and loss values.

中文翻译：

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耦合量子级联激光器中的 PT 对称横模分裂

摘要 通常通过操纵模式有效指数实现的波导中横向模式的分离是目前集成光学领域的兴趣所在，并且已经提出了各种设计。最近，在奇偶校验时间 (PT) 对称下实施非厄米光学器件已经导致采用增益和损耗介质的另一类设备产生了深远的影响。将 PT 对称性引入非厄米系统会产生实数解，而对称性破坏会产生虚特征值。然而，PT对称性在红外器件中的应用非常有限。在这项工作中，我们展示了一种模式分离器，它可以在现实的量子级联激光器（QC 激光器）中分离耦合 PT 对称中的横向模式。