Page 57 - חוברת תזות הנדסה ירוקה 2023

Design and fabrication of a metasurface layer integrated into an optical waveguide structure to improve its power transmission efficiency.
Ravit Yosuopov1; 1ravitush@gmail.com
Prof. Ariela Burg1, Dr. Moshe Zohar1, Dr. Itzhak August1 1Sami Shamoon College of Engineering
Optical communication is based on the transmission of information on an electromagnetic wave )called a carrier wave(, which progresses from the transmitter to the receiver. The medium in which the optical signal propagates is called an optical waveguide. The optical waveguide traps the energy of the propagating wave inside it and transfers it from point to point.
One of the main problems in this field is the wave coupling from the information source into the waveguide medium. The primary cause of this is the reflection phenomenon that occurs during the transition from one medium to another with accompanying dispersion losses )when part of the light is scattered and does not progress along the waveguide but is lost(. As such, there is a motivation for developing new, environmentally friendly, low-cost methods to improve the efficiency of coupling into and transmission of the waveguide.
This research aims to create a unique layer by applying the Dip pen nanolithography )DPN( method atop the waveguide, to improve the coupling efficiency of the energy into the waveguide medium. DPN uses liquid ink on a special tip, positioned at the end of an arm called a ‘cantilever’.
Subgoals are finding optimal conditions for creating metasurfaces on the waveguide )how to clean the surface, temperature, humidity, type of ink, solvent percentage( and characterizing the size of the resulting aggregates )height, diameter, and wetting angle(. Using different types of poly )methyl methacrylate )PMMA( polymer, such as Norland Optical Adhesive )NOA(65, NOA68, and NOA68T, on several waveguides surfaces, like soda-lime glass, SiO2, Si3N4, and indium tin oxide )ITO(.
In our research, we focused on optical coupling efficiency, which we tried to improve by using certain patterns )‘metasurfaces’( on different types of surfaces. We used the NLP 2000 device to create DPN metasurfaces. The fabrication of metasurfaces on waveguide surfaces can improve waveguide efficiency. Optical analyses, related to the measurement of coupling efficiency, will be performed as part of the follow-up research done by means of a narrowband light source with a wavelength adapted to both the metasurface and the waveguide.
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