The enhancement of the reliability of the silicon-based III–V quantum well lasers, especially of those on an on-axis Si (001) substrate, is of great importance now a days for the development of Si-based photonic and even optoelectronic integrated circuits and is really quite challenging. As an experimental advancement, mainly by inserting a pair of InAlAs strained layers separately into the upper and lower AlGaAs cladding layers to effectively prevent the formation of the in-plane gliding misfit-dislocations within the boundary planes of the active region, the longest room-temperature and continuous-wave lifetime of the InGaAs/AlGaAs quantum well lasers on an on-axis Si (001) substrate with a cavity length of 1500 µm and a ridge width of 20 µm has been prolonged from a very initial record of ∼90 s to the present length longer than 31 min. While, the highest continuous-wave operation temperature of another one with a cavity length of 1000 µm and a ridge width of 10 µm has been shown as 103 °C with an extracted characteristic temperature of 152.7 K, further enhancement of the device reliability is still expected and would mainly depend on the level of the threading-dislocation-density reduction in the GaAs/Si virtual substrate.

Silicon-based microcavity quantum dot lasers are attractive candidates for on-chip light sources in photonic integrated circuits due to their small size, low power consumption, and compatibility with silicon photonic platforms. However, integrating components like quantum dot lasers and photodetectors on a single chip remains challenging due to material compatibility issues and mode field mismatch problems. In this work, we have demonstrated monolithic integration of an InAs quantum dot microdisk light emitter, waveguide, and photodetector on a silicon platform using a shared epitaxial structure. The photodetector successfully monitored variations in light emitter output power, experimentally proving the feasibility of this integrated scheme. This work represents a key step toward multifunctional integrated photonic systems. Future efforts will focus on enhancing the light emitter output power, improving waveguide efficiency, and scaling up the integration density for advanced applications in optical communication.

Great advancements in III–V/Si epitaxy have pushed quantum dot lasers to the forefront of silicon photonics. In this work, we designed the structures of evanescent coupled quantum dot distributed feedback lasers with asymmetric gratings, which made significant improvement in on-chip output power while maintaining single-longitudinal-mode stability. The optimal λ/4 phase-shift position (the ratio of the grating length from the rear-end of λ/4 phase-shift to the total grating length) from conventional position of 0.50 to 0.64 allows the ratio of the output power at both sides of silicon waveguide to be increased from 1.0 to 5.9. Moreover, the optimal duty cycle at one side of the phase-shift from 0.50 to 0.8 allows the ratio to be increased from 1.0 to 3.7. Meanwhile, the ratio could be dramatically improved from 1.0 to 9.2 by changed the duty cycle at one side of phase-shift to 0.7 while maintaining the phase-shift position of 0.64. With those designed structures, evanescent coupled quantum dot lasers could challenge the state-of-the-art bonded quantum well lasers and may eventually become ubiquitous and affordable for future commercial production.

Quantum dot (QD) distributed feedback (DFB) lasers have emerged as promising candidates for various applications, including silicon photonic integrated circuits, optical communications, and data centers. However, conventional 1.3 μm InAs/GaAs QD DFB lasers still suffer from high threshold current densities (typically >600 A cm ⁻² ), caused by significant optical losses, which can hardly meet the requirements of energy efficient applications. In this work, a buried grating design is proposed to minimize optical losses caused by grating etch depth nonuniformity, together with optimized regrowth processes. As a result, the threshold current is reduced to a record low value of 4.4 mA, corresponding to a threshold current density of 110 A cm ⁻² . The devices demonstrate a maximum single-facet output power of 5 mW, a slope efficiency of 0.11 W A ⁻¹ , a side-mode suppression ratio of 47 dB, and an operating temperature up to 85 °C. These results represent an important step toward the integration of efficient and reliable 1.3 μm QD DFB lasers in silicon photonic integrated circuits for practical data communication systems.