Design of a single-mode directly modulated orbital angular momentum laser  

作　　者：Xiang Ma Shuang Zheng Jia Liu Quanan Chen Qiaoyin Lu Weihua Guo 马向;郑爽;刘佳;陈泉安;陆巧银;国伟华(Wuhan National Laboratory for Optoelectronics&School of Optical and Electronic Information,Huazhong University of Science and Technology,Wuhan 430074,China)

机构地区：[1]Wuhan National Laboratory for Optoelectronics&School of Optical and Electronic Information,Huazhong University of Science and Technology,Wuhan 430074,China

出　　处：《Chinese Optics Letters》2021年第8期12-17,共6页中国光学快报（英文版）

基　　金：supported by the National Key Research and Development Program of China (No.2016YFB0402304)。

摘　　要：We propose a design of single-mode orbital angular momentum(OAM) beam laser with high direct-modulation bandwidth. It is a microcylinder/microring cavity interacted with two types of second-order gratings: the complex top grating containing the real part and the imaginary part modulations and the side grating. The side grating etched on the periphery of the microcylinder/microring cavity can select a whispering gallery mode with a specific azimuthal mode number, while the complex top grating can scatter the lasing mode with travelling-wave pattern vertically. With the cooperation of the gratings, the laser works with a single mode and emits radially polarized OAM beams. With an asymmetrical pad metal on the top of the cavity, the OAM on-chip laser can firstly be directly modulated with electrical pumping. Due to the small active volume, the laser with low threshold current is predicted to have a high direct modulation bandwidth about 29 GHz with the bias current of ten times the threshold from the simulation. The semiconductor OAM laser can be rather easily realized at different wavelengths such as the O band, C band, and L band.

关 键 词：orbital angular momentum diffraction and gratings vertical emitting lasers microcavity devices semiconductor lasers single mode directly modulated laser 

分 类 号：TN248[电子电信—物理电子学]