Excitation of Silicon Microspheres Resonances with Femtosecond Laser Fabricated Glass Waveguides Hüseyin Ozan Çirkinoğlu a , Ulaş Sabahattin Gökay a , Ali Serpengüzel a , Belén Sotillo b , Vibhav Bharadwaj b , Shane M. Eaton b , and Roberta Ramponi c a Koç University, Microphotonics Research Laboratory, Department of Physics, Rumelifeneri Yolu, Sarıyer, Istanbul 34450 Turkey; b Politecnico di Milano, Department of Physics, Piazza Leonardo da Vinci 32, Milano 20133 Italy; c IFN-CNR, Piazza Leonardo da Vinci 32, Milano 20133 Italy ABSTRACT Optical waveguides were fabricated with femtosecond pulsed lasers on glass and characterized by transmission measurements. Glass waveguides were later used for excitation of the whispering gallery modes in a silicon microsphere. The coupling between the silicon microsphere and the femtosecond laser inscribed optical waveguide was simulated in both 90° elastic scattering and 0° transmission spectra. The silicon microsphere whispering gallery modes are available for both in the transverse electric and transverse magnetic polarizations with a spectral mode spacing of 0.25 nm. Optical resonances on silicon microsphere integrated with femtosecond laser written optical waveguides may lead to future quantum optical communication devices. Keywords: femtosecond laser written optical waveguide, generalized Lorenz-Mie theory, microsphere, optical microcavities, silicon photonics, whispering gallery mode. 1. INTRODUCTION Whispering gallery modes (WGMs) are morphology dependent resonances (MDRs), which occur on the surface of circular cavities such as microspheres. 1 Optical properties of the WGMs, such as high quality factors in relatively small volumes, resulted in the integration of WGMs in various photonics applications. 2 Excitation of WGMs in microspheres depend on total internal reflection (TIR) and has been performed using prisms, 3 tapered fibers, 4 and optical fiber half couplers (OFHCs). 5 Moreover, thriving femtosecond laser micromachining techniques 6,7 opens the way for more efficient, stable, and controllable excitation in more compact, and robust geometries such as femtosecond laser inscribed glass optical waveguides. 8,9,10 Here, we present results for the characterization of the femtosecond laser inscribed optical waveguides in glass. We also performed the analysis of the excitation of a 500 μm radius silicon (n = 3.48) microsphere WGMs at 90º elastic scattering and 0º transmission spectra excited by using femtosecond laser inscribed glass waveguides in the near-infrared optical communication bands. Nanoengineering: Fabrication, Properties, Optics, and Devices XIII, edited by Eva M. Campo, Elizabeth A. Dobisz, Louay A. Eldada, Proc. of SPIE Vol. 9927, 99271T · © 2016 SPIE CCC code: 0277-786X/16/$18 · doi: 10.1117/12.2239326 Proc. of SPIE Vol. 9927 99271T-1 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 06/08/2017 Terms of Use: http://spiedigitallibrary.org/ss/termsofuse.aspx