Direct epitaxial growth of III-V light sources on Si photonic chips is promising to realize low-cost and high-functionality photonic integrated circuits. Historically, high temperature reliability of such devices has been the major roadblock due to crystalline defects from heteroepitaxy. Here, by reducing the threading dislocation densities to ∼ 1 × 1 0 6 c m − 2 and efficiently removing misfit dislocations above and below the active region, 1.3 µm InAs quantum-dot lasers directly grown on industry standard on-axis Si (001) show record-breaking reliability at 80°C. The hero device shows minimum degradation after more than 1200 h of constant current stress. Statistical analysis shows an extrapolated lifetime of over 22 years for the median devices, bringing these devices one big step closer to real world applications.

Distributed feedback (DFB) lasers represent a central focus for wavelength‐division‐multiplexing‐based transceivers in metropolitan networks. Here, the first 1.3 µm quantum dot (QD) DFB lasers grown on a complementary metal‐oxide‐semiconductor (CMOS)‐compatible (001) Si substrate are reported. Temperature‐stable, single‐longitudinal‐mode operation is achieved with a side‐mode suppression ratio of more than 50 dB and a threshold current density of 440 A cm−2. A single‐lane rate of 128 Gbit s−1 with a net spectral efficiency of 1.67 bits−1 Hz−1 is demonstrated, with an aggregate total transmission capacity of 640 Gbit s−1 using five channels in the O‐band. Apart from the QD active region growth, the overall fabrication is essentially identical to the commercial process for quantum well (QW) DFB lasers. This provides a process‐compatible path for QD technology into commercial applications previously filled by QW devices. In addition, the capability to grow laser epi across entire CMOS‐compatible (001) Si wafers adds extra benefits of reduced cost, improved heat dissipation, and manufacturing scalability. Through direct epitaxial integration of III–Vs and Si, one can envision a revolution of the photonics industry in the same way that CMOS design and processing revolutionize the microelectronics industry. This is discussed from a system perspective for on‐chip optical interconnects.

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We describe the effectiveness of filter layers, which displace misfit dislocation (MD) formation away from the active region, in improving high temperature reliability of epitaxially integrated InAs quantum dot lasers on on-axis silicon substrates. We find that inserting these “trapping layer (TL)” filters at either 80 nm or 180 nm from the active region substantially reduces device degradation at 60 °C. After 3000 h of continuous operation, the best trapping-layer-free device shows a 55% increase in threshold current while the best trapping layer (TL) devices each show less than a 9% increase. We explain these findings by correlating changes in individual device performance to changes in misfit dislocation (MD) structure. All MDs in devices without TLs show evidence of recombination enhanced dislocation climb (REDC); in contrast, adding trapping layers at 180 nm or 80 nm reduces the fraction of electrically active MDs to 9% and 1%, respectively. Reliability data after 3000 hours suggest that incorporating trapping layers a shorter distance from the active region (80 nm) is more effective than incorporating these layers further away. We conclude by identifying the mutually and self-reinforcing failure processes associated with REDC that TLs significantly remediate: increasing dislocation line length, increasing point defect densities, and increasing junction temperature. Overall, understanding and controlling crystal defects continues to be the most impactful avenue toward integrating light sources on photonic integrated circuits and closing the gap with native-substrate lasers.