1.3 µm Quantum Dot-Distributed Feedback Lasers Directly Grown on (001) Si

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.