O-band quantum-dot DFB lasers combining high-efficiency, high-linearity, optical-feedback tolerated, and high-temperature operation

The rapid expansion of large-scale artificial intelligence data centers and the growing demand for high-performance radio-over-fiber (RoF) systems necessitate high-efficiency, ultra-low noise, highly linear, and thermally stable lasers. Here we demonstrate a high-performance O-band InAs/GaAs quantum-dot (QD) distributed-feedback (DFB) laser architecture incorporating a laterally coupled, shallow-etched sidewall grating within a trapezoidal ridge waveguide. At room temperature, the fabricated devices achieve a single-facet output power of 70 mW with an impressive slope efficiency of 0.372 W·A −1 , while maintaining excellent single-mode emission with a side-mode suppression ratio (SMSR) up to 61 dB. For optical interconnect applications, these lasers exhibit exceptional thermal stability, sustaining stable single-mode operation at 125°C with an output power exceeding 6 mW. Furthermore, they show robust tolerance to optical feedback, with the SMSR remaining over 50 dB even at a returned power level of −15 dB , enabling isolator-free integration. For RoF applications, the devices achieve an ultra-low relative intensity noise (RIN) of <−170 dB / Hz over the 4–22 GHz frequency range and demonstrate high linearity, with an input 1 dB compression point ( IP 1 dB ) of approximately 25 dBm and a third-order intercept point ( IIP 3 ) of approximately 34.4 dBm. The demonstrated architecture represents a significant advance, as it simultaneously optimizes multiple critical performance metrics—efficiency, thermal stability, feedback resilience, low-noise performance, and large-signal linearity—within a single device. The simple, regrowth-free fabrication process is compatible with heterogeneous integration platforms, making it a highly promising solution for future wafer-scale manufacturing of QD lasers on silicon or thin-film lithium niobate (TFLN) wafers.