Nanolasers: Second-order intensity correlation, direct modulation and electromagnetic isolation in array architectures

Ideal integrated light emitters for optical interconnects should be compact in size, high in modulation bandwidth, efficient in energy consumption and tunable in frequency. Nanolasers are excellent candidates for such an application. In this article, we review and offer further in-depth analyses in three key aspects of recent nanolaser research, including second order intensity correlation, g²(τ), characterizations, direct modulation and electromagnetic isolation in a dual nanolaser system. For coherence characterization, we review a technique exploiting not only the photon bunching peak, but also the g²(τ) pulse width to determine the spontaneous emission (SE), amplified SE and lasing regimes of a nanolaser with a high SE factor, β. We show that this technique is applicable for lasers with β′s ranging from 10⁻⁵ to unity. Additionally, we demonstrate the first direct current modulation of an electrically pumped metallo-dielectric nanolaser (MDNL) at 30 MHz. Considering the viability of nanolasers for dense integration, we then review the electromagnetic coupling between two closely spaced MDNLs and identify two practical methods to eliminate such coupling. Lastly, we review the state-of-the-art development in and offer future perspectives on three other important areas of nanolaser research ― integration with silicon photonics, wide-range frequency tuning and dual nanolaser dynamics.