Thesis Type:MSc thesis
In this work I report on the development of a platform of a polymeric waveguide composed of Cytop as the cladding and PFCB as the core. These two polymers were chosen due to their low loss in the optical communication regime (0.26 dB/cm for PFCB core and 0.022dB/cm for Cytop cladding). PFCB and Cytop have refractive indexes of 1.48 and 1.34 respectively and therefore offer high index contrast in comparison to glass waveguides. PFCB was chosen as the waveguide core since it has been proven a good host for nanocrystals (NCs).
In this work a lot of effort was invested in making the fabrication process compatible with semiconductor NCs that will in the long term be mixed in the PFCB core. Doping the core with nanocrystals is of interest, since the NCs properties are diverse, flexible and controllable. Choosing NCs with high third order susceptibility will allow us to fabricate nonlinear waveguides. Furthermore,specifying the NCs shape and size will allow us to align them by applying external electric voltage and by that enhance the macroscopic nonlinear properties of the composite.
Two fabrication configuration are proposed. Both are aimed at fabricating a square waveguide. The first configuration is the ridge-method where the PFCB core undergoes reactive ion etching (RIE).This method carries on with previously proposed methodology at the Photonic Devices Laboratory of Dr. Marom , however several key improvements were made.
The second configuration is the trench-method where only the Cytop undergoes RIE. By that method we wish to prevent roughness that might occur in the alternative method due to etching a composite made of PFCB and the NCs at the same time. In addition not all NC materials we would like to use are allowed into the RIE chamber since they may cause contamination to the RIE machine. Replacing the ridge method with the trench one will obviously overcome this obstacle. However both methods have their own challenges. In this work I tried to overcome some of the challenges and to produce reliable and reproducible method for fabricating a square polymeric waveguide compatible with NCs.