Publications by authors named "Yuzhou G N Liu"

Article Synopsis
  • A coupled distributed feedback (DFB) laser system using AlGaAs/GaAs semiconductor is developed, emitting light near 820 nm and utilizing a shared Bragg grating for dual-frequency operation.
  • The system achieved dual-mode operation with a 4.2 nm wavelength difference, resulting in a 1.86 THz beat frequency and producing 14.7 mW output power at a current of 195 mA.
  • This new design simplifies the manufacturing process for dual-mode DFB lasers and enhances compatibility with high-frequency photodetectors, while potentially allowing for tunable beat frequencies.
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From biological ecosystems to spin glasses, connectivity plays a crucial role in determining the function, dynamics, and resiliency of a network. In the realm of non-Hermitian physics, the possibility of complex and asymmetric exchange interactions ([Formula: see text]) between a network of oscillators has been theoretically shown to lead to novel behaviors like delocalization, skin effect, and bulk-boundary correspondence. An archetypical lattice exhibiting the aforementioned properties is that proposed by Hatano and Nelson in a series of papers in late 1990s.

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Topological insulator lasers (TILs) are a recently introduced family of lasing arrays in which phase locking is achieved through synthetic gauge fields. These single frequency light source arrays operate in the spatially extended edge modes of topologically non-trivial optical lattices. Because of the inherent robustness of topological modes against perturbations and defects, such topological insulator lasers tend to demonstrate higher slope efficiencies as compared to their topologically trivial counterparts.

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The synergetic use of gain and loss in parity-time symmetric coupled resonators has been shown to lead to single-mode lasing operation. However, at the corresponding resonance frequency, an ideal ring resonator tends to support two degenerate eigenmodes, traveling along the cavity in opposite directions. Here, we show a unidirectional single-moded parity-time symmetric laser by incorporating active S-bend structures with opposite chirality in the respective ring resonators.

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