Silicon photonics, due to its compatibility with the CMOS platform and unprecedented integration capability, has become the preferred solution for the implementation of next generation optical interconnects. However, current Si photonics require on-chip integration of several materials, including III-V for lasing, doped silicon for modulation and Ge for detection. The very different requirements of these materials result in complex fabrication processes that offset the cost-effectiveness of the Si photonics approach. We are developing an alternative route towards the integration of optoelectronic devices in Si photonic, relying on the use of single wall carbon nanotubes (SWNTs). SWNTs can be considered as a Si compatible material able to emit, modulate and detect near-infrared light. Hence, they hold a unique potential to implement all active devices in the Si photonics platform. In addition, solution processed SWNTs can be integrated on Si using spin-coating techniques, obviating the need of complex epitaxial growth or chip bonding approaches. Here, we report on our recent progress in the coupling of SWNTs light emission into optical resonators implemented on the silicon-on-insulator (SOI) platform.

Silicon photonics has emerged as a very promising technology platform for the implementation of high-performance, low-cost, ultra-compact circuits that can monolithically cointegrate electronic, opto-electronic and optic functionalities. However, Si neither has efficient light emission or detection in the telecom wavelength range, nor exhibits efficient electro-optic Pockels effect, hindering the implementation of integrated active devices like sources, detectors, or modulators. Current approaches relay on different materials to provide active functionalities in Si photonics, resulting in highly complex integration schemes that compromise cost-effectiveness. Semiconducting single-wall carbon nanotubes (SWNTs) are capable of emitting and detecting near-infrared light at room temperature and exhibit intrinsically fast electro-optic effects. They have also proven promising uses in micro-electronic devices, making them an ideal material to provide active functionalities in the Si photonic platform. In this work, we propose and experimentally validate the possible use of slot photonic waveguides to improve interaction between SWNTs and Si waveguide modes. Fabricated Si slot micro-ring shown an experimental ~ 60% photo-luminescence improvement compared to previous demonstration based on Si strip waveguide resonators. These results prove the potential of Si slot waveguides for the implementation of efficient SWNT-based Si photonic devices.

We report on the strong photoluminescence enhancement from carbon nanotubes integrated in silicon microring resonators under two pumping configuration: surface-illuminated pumping and collinear pumping. Extremely efficient rejection of non-resonant photoluminescence is observed.

Semiconducting carbon nanotubes are an emerging material for photonics. We report on the enhancement of semiconducting carbon nanotubes photoluminescence with silicon microring resonators. Polyfluorene extracted semiconducting carbon nanotubes, deposited on such resonators, display sharp emission peaks superposed to nanotube emission, which is attributed to the interaction with the cavity modes of the microring resonators. Ring resonators with radii of 5 and 10  μm were used, to demonstrate the tuning of the spectral distance between two successive emission resonances. Quality factors ranged between 3000 and 4000 in emission. These are among the highest values reported so far for carbon nanotubes coupled with optical microcavity on the silicon platform, highlighting the bright perspectives for carbon nanotube photonics.

Single Wall Carbon Nanotubes (SWNT) properties are highly sensitive to theirdirect chemical, dielectric and mechanical environment. Depending on the application field, such as, photonics, electronics, sensors, the interaction strength with theenvironment has to be modulated and fully controlled. PFO (polyfluorene polymer), commonly used for wrapping carbon nanotubes in selective purification process acts also as an effective isolant due to its natural helicity matching with SWNT diameter and its wide bandgap in the UV. Here we report on a selective annealing process under a low pressure of oxygen to tune the PFO coverage of SWNT networks deposited on a substrate. The impact of the annealing on both SWNT network and PFO was probed by AFM, Raman, absorption, photoluminescence and electrical experiments.

This paper reports on recent results on the integration of carbon nanotubes on the silicon photonic platform. Light coupling from carbon nanotubes in a fully integrated silicon resonator will be presented.

The rise of efficient extraction techniques triggered a renewal of interest in semiconducting carbon nanotubes (s-SWNT) research. It represents a great interest for optoelectronics, with outstanding properties in field-effect transistor, and s-SWNT ability to efficiently emit light in the near-IR range. In particular, polyfluorene (PFO) wrapped s‑SWNT (s-SWNT@PFO) display strong photoluminescence, and could be coupled with photonic devices such as microring resonators [1,2] to control photoluminescence linewidth and enhance photoluminescence intensity. The main challenge for using s-SWNT@PFO in optoelectronics lies in the difficulty to establish good electrical contact with a PFO embedded carbon nanotube, and existing studies only focused on optical pumping of carbon nanotubes networks, without addressing issues of electrical driving. We propose to investigate these issues using s-SWNT@PFO networks deposited on patterned substrate (Figure). The network formation process allow to control nanotube density, while the amount of remaining metallic nanotube in the network could be adjusted at the extraction phase. A selective annealing process under low pressure is used to tune PFO wrapping around the nanotubes. The resulting s-SWNT@PFO networks are then probed by AFM, Raman spectroscopy, absorption, photoluminescence and electrical experiments.