Enhanced performance of 1064 nm high-strain laser diodes via triangular quantum well design

High indium composition in 1064 nm InGaAs quantum well (QW) increases strain and defect density, limiting reliability and efficiency of laser diodes (LDs). This study investigates triangular-QWs (TQWs) as a means to overcome these limitations. Theoretical analyses using the Matthews-Blakeslee model and the k·p model predicted that TQWs have superior crystal quality and lower transparent current density than square-QWs (SQWs). Experimentally, the 16 nm TQW LD exhibited a 52% increase in carrier lifetime, a 0.06 A reduction in threshold current, and a 0.50 mΩ decrease in series resistance compared with the 8 nm SQW device. The 16 nm TQW LD achieved a peak power conversion efficiency of 72.1% at 4 mm cavity, among the highest for 1064 nm LDs. The double-TQW structure increased saturation power by 54% through improved carrier trapping and thermal stability. Triangular-QWs thus offer a promising pathway towards efficient and reliable LDs in high-strain regimes.