Department of Electronic Engineering, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong.
Shun Hing Institute of Advanced Engineering, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong.
Sci Rep. 2016 Nov 28;6:37688. doi: 10.1038/srep37688.
We propose a new type of semiconductor lasers by implementing the concept of parity-time symmetry in a two-dimensional circular Bragg grating structure, where both the real and imaginary parts of the refractive index are modulated along the radial direction. The laser modal properties are analyzed with a transfer-matrix method and are verified with numerical simulation of a practical design. Compared with conventional distributed-feedback lasers with modulation of only the real part of refractive index, the parity-time-symmetric circular Bragg lasers feature reduced threshold and enhanced modal discrimination, which in combination with the intrinsic circularly symmetric, large emission aperture are clear advantages in applications that require mode-hop-free, high-power, single-mode laser operation.
我们通过在二维圆形布拉格光栅结构中实现宇称时间对称的概念，提出了一种新型半导体激光器，其中折射率的实部和虚部都沿着径向进行调制。我们使用传输矩阵方法分析了激光模式特性，并通过实际设计的数值模拟进行了验证。与仅调制折射率实部的传统分布式反馈激光器相比，宇称时间对称的圆形布拉格激光器具有更低的阈值和更高的模式鉴别能力，再加上其固有的圆形对称、大发射孔径，在需要无模跳、高功率、单模激光运行的应用中具有明显优势。
