Electrically Injected Metamaterial Grating DFB Laser Exploiting an Ultra-High Q Electromagnetic Induced Transparency Resonance for Spectral Selection

The study shows that, in waveguide (WG) configuration, the coupling of a 2D plasmonic metamaterial grating (MMG) having a conventional Bragg period along the guide but a distinct period along the transverse axis can lead to Electromagnetically-Induced-Transparency (EIT) behavior. This epitomizes that metamaterials, as functional photonic building blocks, can lead to low losses in many standard devices if properly designed. The study reported the observation in passive WGs of a marked Fano-type EIT resonance with record high-quality factor: Q = 5000 and contrast >20 dB. Unlike any standard metal grating, MMG-assisted waveguides exhibit strong grating coupling strength and low-loss properties simultaneously. This concept is further applied to demonstrate single-frequency-emission electrically-injected Distributed Feedback (DFB) lasers in the near-infrared telecom domain. The key point is that laser emission occurs at the peak of EIT, i.e., the maximum in transmission. It therefore addresses one of the main critical issues of DFB lasers related to the single frequency yield. The laser performances are state-of-the-art (I_th < 20 mA, P_max> 20 mW at I = 200 mA, SMSR > 50 dB, optical feedback tolerance >−21 dB compliant with IEEE 802.3 standard). The presented approach, compatible with existing industrial technologies, is promising for real-life telecom applications.