High-bandwidth directly modulated quantum-well-intermixed membrane feedback laser on silicon

The rapid scaling of AI clusters in cloud data centers is driving unprecedented demand for short-reach, high-density optical interconnects with stringent energy constraints. We present a directly modulated membrane III-V-on-SiO₂/Si distributed-reflector laser employing quantum-well-intermixed passive Bragg reflectors that provide fabrication-tolerant and stable optical feedback, enabling robust bandwidth enhancement at a low operating energy via the detuned-loading (DL) effect. A fabricated device operating in the O-Band with a designed grating coupling coefficient of approximately 400 cm^-1 exhibits DL-induced relaxation oscillation frequency of up to ∼24 GHz and a record 3-dB DL-enhanced modulation bandwidth exceeding 36 GHz, representing +45% bandwidth improvement compared to prior reports. The laser supports 128 Gb/s PAM-4 operation with a bit-error rate below 3.8 × 10^-3 at a laser operating energy of just 0.21 pJ/bits, suitable for next-generation co-packaged optics and short-reach intra- and inter-rack connectivity.