High-reliable and high-speed 1.3 μm complex-coupled distributed feedback buried-heterostructure laser diodes with Fe-doped InGaAsP/InP hybrid grating layers grown by MOCVD

In this paper, we report the fabrication of high-reliability and high-speed 1.3 μm complex-coupled distributed feedback (CC-DFB) buried heterostructure (BH) laser diodes (LDs) with Fe-doped InGaAsP/InP hybrid grating layers. High optical coupling coefficient and eminent current confining ability are accomplished by combining the Fe-doped InGaAsP/InP current-blocking-grating (CBG) layers to provide both the distributed-feedback index- and gain-coupling coefficients. Besides, the narrow-stripe BH LDs are implemented by burying the active region with a Fe-doped InP current-blocking layer during the epitaxial regrowth. The fabricated CBG CC-DFB BH LDs at 20 °C shows a low threshold current of 5.3 mA, a maximum light output power of 36 mW at 100 mA, a high slope efficiency of 0.41 mW/mA, and a side-mode suppression ratio (SMSR) of 42 dB at twice the threshold. In addition, these LDs exhibit a maximum operation temperature of 125 °C, an extremely low threshold current of 15.8 mA at 90 °C, a small variation in slope efficient of only -1 dB in the temperature range from 20 °C to 80 °C, and a characteristic temperature of 77 K and 56 K between 20 °C and 60 °C, and 70 °C and 120 °C, respectively. Furthermore, these 1.3 μm CBG CC-DFB BH LDs exhibit a high-speed characteristic up to 11.8 GHz at room temperature and an estimated median lifetime of more than 1.1 × 10⁵ h or 12.5 years at 5 mW and 85 °C.