title: Parity-time-symmetric circular Bragg lasers: a proposal and analysis.
abstract: 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.
authors.affiliation: 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.
authors.forename: Jiahua
authors.initials: J
authors.lastname: Gu
authors.affiliation: Department of Electronic Engineering, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong.
authors.forename: Xiang
authors.initials: X
authors.lastname: Xi
authors.affiliation: 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.
authors.forename: Jingwen
authors.initials: J
authors.lastname: Ma
authors.affiliation: Department of Electronic Engineering, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong.
authors.forename: Zejie
authors.initials: Z
authors.lastname: Yu
authors.affiliation: 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.
authors.forename: Xiankai
authors.initials: X
authors.lastname: Sun