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Lasing in a Hybrid Rare‐Earth Silicon Microdisk

Silicon photonics is an ideal platform for low‐cost, energy‐efficient, and high‐performance optical microsystems. However, because silicon is an inefficient light emitting material, the development of simple, inexpensive, and scalable monolithic amplifiers and light sources has been a significant challenge. Here, optical gain and lasing in an ultra‐compact hybrid rare‐earth silicon microdisk resonator are reported. The microdisk design is straightforward and compatible with the fabrication steps and device dimensions available in all silicon photonics foundries, while the thulium‐doped tellurite gain medium is added in a low‐temperature single‐step sputter deposition. This approach allows for low‐cost and high‐volume wafer‐scale manufacturing and co‐integration of rare‐earth amplifiers and light sources with silicon passive and active devices with no adjustment to standard process flows. The hybrid laser is pumped at standard telecom wavelengths around 1.6 µm and exhibits stable single‐mode emission at 1.9 µm, with an internal slope efficiency of 60% and >1 mW on‐chip output power. The laser is highly promising for emerging communications and sensing applications and opens new possibilities for the development of monolithic rare‐earth optical amplifiers and lasers directly on silicon.