On-Chip Broadband Multiwavelength Microlaser Array in Visible Region

On-chip integrated microlaser sources are critical components in silicon (Si) photonics, which has become one of the leading photonic integrated circuits (PICs) technologies due to low cost, eco-friendly, large-scale integration and inherent compatibility for complementary metal-oxide-semiconductor (CMOS) manufacturing processes. Until now, however, it still remains a significant challenge to achieve an active microlaser with a quality factor of up to 10⁴ and heterogeneous integration of multiple broadband wavelength-tunable microlasers for Si-based PICs. Here, a scalable strategy is reported to realize simultaneous integration of multiwavelength GaN-based microdisk laser arrays on Si(100) substrates. The microlaser exhibits a high-quality factor of 13 138 and a low threshold density of 57.85 µJ cm⁻². By precisely modulating the microdisk size and/or shape and thus the corresponding cavity loss, the lasing wavelength can be dynamically tuned over a large spectral range from 455 to 503 nm, which is physically unraveled by the gain profile shifting for different threshold energy levels conditions. This study opens a new path toward the realization of on-chip integrated broadband multiwavelength laser sources for Si-PICs platform, where only an epi-wafer and a single round of wafer bonding processes are needed.