Ultralow Threshold 1.3-μm InGaAsP–InP Compressive-Strained Multiquantum-Well Monolithic Laser Array for Parallel High-Density Optical Interconnects

An ultralow-threshold 1.3-μm InGaAsP–InP 10-element monolithic laser array is achieved through careful optimization of a strained multiquantum-well active layer, especially the amount of strain, the well thickness, the barrier thickness, the number of wells, and the active layer width. This array has a record-low threshold current, highly uniform threshold current characteristics (1.3 ± 0.09 mA and slope efficiency of 0.37 ± 0.01 W/A), extremely low operating current of 14 mA under 5-mW output power, and long-term reliability. This array is suitable as light sources for a parallel high-density optical interconnection system. In addition, a record low CW threshold current of 0.58 mA at 20 °C and 1.62 mA at 90 °C, as a long-wavelength laser, is obtained by employing a short cavity (100 μm) with high-reflection coatings.