Design of an Erbium-Organic Slot Waveguide on Silicon on Insulator for C Band Optical Amplification
In the field of integrated photonics, the emerging application of molecular materials to the integrated photonics led to the definition of the silicon organic hybrid (SOH) technology, that represents a solution to bring new functionalities to the intrinsically passive Silicon photonics. Slot waveguide structures enable SOH for light confinement and guiding into the dielectric slot between two silicon rails, even if exhibiting a lower refractive index than silicon. Erbium-doped molecular materials that show electroluminescence besides to traditional photoluminescence from optical pumping, may provide an interesting solution for processing of electrically-supplied IR emitting blocks in a silicon photonic integrated circuits (PICs). Among the erbium-doped molecular materials, erbium quinolines (ErQ) were already used to demonstrate IR electroluminescence, solution processing and very preliminary IR lasing on Silicon substrates. To optimize the design of the ErQ-coated slot waveguide in terms of optical confinement factor for input wavelength set at 1550 nm, the Wave Optics Module of COMSOL Multiphysics® 5.4 was used. The design parameters of the slot waveguide shown in Figure 1, i.e. silicon rail width and slot width, were optimized, whereas the rail thickness is considered imposed by the commercially available silicon on insulator (SOI) substrates, having 260 nm thickness. The results of the optimization led to the nano-fabrication of the ErQcoated slot waveguide that is currently under optical characterization.
