A research team from Japan has developed an integrated, high-speed and on-chip blackbody emitter based on graphene. The team reports that the device operated in NIR region including telecommunication wavelengths. A fast response time of ~ 100 ps, which is ~ 105 higher than the previous graphene emitters, has been experimentally demonstrated for single and few-layer graphene, the emission responses can be controlled by the graphene contact with the substrate depending on the number of graphene layers.
The team stated that graphene light emitters are greatly advantageous over conventional compound semiconductor emitters because they can be integrated on silicon chips due to simple fabrication processes of graphene emitters and direct coupling with silicon waveguide through an evanescent field. Because graphene can realize high-speed, small footprint and on-Si-chip light emitters, which are still challenges for compound semiconductors, the graphene-based light emitters can open new routes to highly integrated optoelectronics and silicon photonics.
The mechanisms of the high-speed emission are elucidated by performing theoretical calculations of the heat conduction equations considering the thermal model of emitters including graphene and a substrate. The simulated results indicate that the fast response properties can be understood not only by the classical thermal transport of in-plane heat conduction in graphene and heat dissipation to the substrate but also by the remote quantum thermal transport via the surface polar phonons (SPoPhs) of the substrates
In addition, real-time optical communication with graphene-based light emitters was experimentally demonstrated, indicating that graphene emitters are novel light sources for optical communication. Furthermore, the team fabricated integrated two-dimensional array emitters with large-scale graphene grown by chemical vapour deposition (CVD) method and capped emitters operable in air, and carried out the direct coupling of optical fibers to the emitters owing to their small footprint and planar device structure.