Enhanced high brightness DBR tapered diode laser based on polarization match
Mengyao Lv, Zhiyu Zhou, Yuwen He, Pengfei Xie, Yi Li, Haomiao Wang, Weichuan Du, Songxin Gao, Chun Tang, Deyong Wu
Abstract
Tapered diode lasers, composed of an index-guided ridge waveguide and a gain-guided tapered amplifier, are affected by polarization mismatch between the ridge and tapered sections. Beam quality deterioration is caused by TM high-order modes generated in the ridge section. Under high current injection, these TM modes are further amplified in the tapered section due to polarization mismatch, leading to a decrease in the laser output brightness. In this paper, a combination of deep etching in the ridge section and compressive stress in the tapered section is employed to obtain a fundamental mode seed source with a high TE degree of polarization (DOP), simultaneously improving the polarization match between the ridge and tapered sections. The fabricated tapered diode laser achieves a beam quality factor of M 2 (1/e 2 ) = 1.2 at an output power of 11.57 W. The peak electro-optical efficiency is 59.8%, and the maximum output brightness reaches 936 MW·cm −2 ·sr −1 .