September 1, 2021

Open call: Post doctoral researchers, graduate research associates, and undergraduate student researchers

  • Post docs, graduate students, and undergraduate students interested in conducting research in Integrated Optics and Photonics with Prof. Reano should contact Prof. Reano directly at Please include your CV in your email. Thank you.

August 24, 2021

Prof. Reano leads team of faculty awarded a 2021 Major Research Instrumentation (MRI) Award from the National Science Foundation

  • State-of-the-art chemical mechanical polishing (CMP) for frontier research and synergistic education is on its way to Ohio State. CMP has emerged as a technique for planarizing surfaces with resulting surface roughness down to the sub-nanometer root-mean-square level. Ultra-flat surfaces are enabling for microelectronics, optoelectronics, micro-electro-mechanical systems, and advanced device architectures. In addition to the support from NSF, the effort is supported by the Ohio Department of Higher Education, the OSU Office of Research, the College of Engineering, the Department of Electrical and Computer Engineering, and the Electroscience Laboratory.

August 12, 2021

Ryan Patton publishes research on orbital angular momentum in silicon photonic waveguides in IEEE Photonics Journal

  • Ryan J. Patton and Ronald M. Reano, “Higher Order Mode Conversion from Berry’s Phase in Silicon Optical Waveguides,” IEEE Photonics Journal doi: 10.1109/JPHOT.2021.3104180.
  • Summary: We present mode conversion between the higher order Ex21 and Ex12 optical modes in an out-of-plane silicon waveguide exhibiting Berry’s phase. Superpositions of the Ex21 and Ex12 modes form quasi-Laguerre-Gaussian modes with total angular momentum of 1 per photon for a 720 600 nm2 silicon waveguide core. When the waveguide is deflected out-of-plane by 22.5, 50% mode conversion occurs from the Ex21 mode to the Ex12 mode. The concatenation of a quarter wavelength straight section results in an output with 0.89 orbital and 0.15 spin angular momentum per photon. Orbital angular momentum generation in a waveguide platform provides a route for on-chip applications that utilize the angular momentum of light for sensing, optical manipulation, non-linear optics, and communications.

August 5, 2021

Professor Reano teaches on-line summer short course on Classical and Quantum Integrated Photonics

  • On-line participants from academia and industry attended a live half-day short course via the ElectroScience Laboratory (ESL) Consortium on Electromagnetics and Radio Frequencies (CERF) at Ohio State. The introductory survey course covered waveguide linear optics, elements of nonlinear optics, and elements of quantum optics from the perspective of theory and experimental results. Results from Prof. Reano’s research group were discussed including recent measurements of spontaneous parametric down conversion from nanophotonic lithium niobate on insulator waveguides.

June 1, 2021

Karan Prabhakar presents ion-sliced lithium niobate research results at 64th International Conference on Electron, Ion and Photon Beam Technology and Nanofabrication

  • Karan Prabhakar, Ryan J. Patton and Ronald M. Reano, “Stress reduction and wafer bow accommodation for the fabrication of thin film lithium niobate on oxidized silicon,” in 64th International Conference on Electron, Ion, and Photon Beam Technology and Nanofabrication.
  • Summary: Sub-micrometer thick lithium niobate on insulator (LNOI) is a promising integrated photonic platform that provides optical field confinement and optical nonlinearity useful for state-of-the art electro-optic modulators and wavelength converters. Bonding to a silicon substrate is advantageous for electronic-photonic integration but is challenging because of debonding and cracking due to thermal expansion coefficient (TEC) mismatch between Si and LN. In this work, fabrication of ion sliced LNOI on a Si handle wafer is achieved by selecting optimized wafer thicknesses informed by structural modeling and accommodating for dissimilar wafer bows using a bonding apparatus.

May 13, 2020

Tyler Nagy and Karan Prabhakar present research on poling of ion-sliced lithium niobate at the Conference on Lasers and Electro-Optics

  • Jonathan Tyler Nagy, Karan Prabhakar, and Ronald M. Reano, “In situ temporal periodic poling of lithium niobate thin films,” in Conference on Lasers and Electro-Optics (CLEO): 2020, OSA Technical Digest (online) (Optical Society of America, 2020), paper SW3F.3.
  • Abstract: We repeatedly pole and unpole a lithium niobate thin film second harmonic generator while monitoring the switching of the optical output. Increasing asymmetry in the poling waveform results in increasing optical extinction ratio.

May 12, 2020

Ryan Patton presents research on orbital angular momentum in silicon waveguides at the Conference on Lasers and Electro-Optics

  • Ryan J. Patton and Ronald M. Reano, “Generating light with orbital and spin angular momenta in silicon waveguides using Berry’s phase,” in Conference on Lasers and Electro-Optics (CLEO): 2020, OSA Technical Digest (online) (Optical Society of America, 2020), paper STu3J.4.
  • Abstract: We utilize out-of-plane waveguides exhibiting Berry’s phase to generate guided light carrying angular momentum. The normalized output orbital and spin angular momenta are computed to be 0.85 and 0.15 per photon, respectively, at 1550 nm wavelength.

May 5, 2020

Professor Reano discusses the Optics and Photonics focus area in the Electrical and Computer Engineering Department

  • Optics and Photonics at OSU provides students with opportunities to pursue a variety of courses, conduct experimental and theoretical research, and network through international societies.  Link to video.

December 9, 2019

Professor Reano’s research group recognized with Electroscience Lab Test of Time Award

  • For the widely referenced 2014 paper entitled “Hybrid silicon and lithium niobate electrooptical ring modulator” by Li Chen, Qiang Xu, Michael G. Wood, and Ronald M. Reano published in Optica.  Link to news article.

September 17, 2019

Tyler Nagy presents research at Frontiers in Optics / Laser Science Conference in Washington DC

  • Tyler Nagy and Ronald M. Reano, “Fabricating Periodically Poled Lithium Niobate Thin Films with Sub-Micrometer Fundamental Period,” in Frontiers in Optics / Laser Science (FiO): 2019, OSA Technical Digest (online) (Optical Society of America, 2019), paper JTu3A.10.
  • Abstract: We present sub-micrometer periodic poling of ion-sliced x-cut magnesium oxide doped lithium niobate thin films. The poled domains are characterized by piezoresponse force microscopy. A fundamental period of 776 nm is achieved.

August 7, 2019

Professor Reano teaches summer short course on Chip-Scale Nonlinear Integrated Photonics

  • Students, researchers, practicing engineers, and on-line participants attended a half-day short course at Ohio State University covering integrated nonlinear photonics.  The integrated photonics concept is the application of thin-film technology to optical circuits and devices for the purpose of achieving high-performance optical systems with advantages in miniaturization, mechanical stability, and economies of scale.  On the chip-scale, optical waveguides can exhibit high electric field intensities at low absolute power levels, resulting in efficient nonlinear optical devices. The short course introduced the fundamentals of nonlinear optics in planar optical waveguides designed to exploit fundamental nonlinear optical effects. Applications in telecommunications, interconnects, sensors, and radio-frequency (RF) photonics were discussed throughout the course within a theoretical and experimental context.

June 26, 2019

Tyler Nagy publishes research in Optical Materials Express

  • Jonathan Tyler Nagy and Ronald M. Reano, “Reducing leakage current during periodic poling of ion-sliced x-cut MgO doped lithium niobate thin films,” Optical Materials Express 9, 3146-3155 (2019).
  • Abstract: Ion-sliced lithium niobate thin films offer high optical confinement over their bulk counter parts, enabling compact and efficient nonlinear optics. Quasi-phase matching by periodic poling of thin film lithium niobate remains challenging, however, due to large leakage currents, especially in magnesium oxide doped lithium niobate, which is used in bulk to reduce photorefractive damage. Here we present fabrication and poling details of 700 nm thick x-cut magnesium oxide doped lithium niobate thin films using electric field poling. We introduce a silicon dioxide insulation layer under co-planar electrodes to reduce leakage current. Rounded tips are utilized to encourage nucleation at the center of the electrodes. Uniform domains with 7.5 µm period and 50% duty cycle are achieved. The poling characteristics are compared to bulk lithium niobate, with and without the silicon dioxide insulation layer. The domains are characterized by piezoresponse force microscopy, hydrofluoric etching, and waveguide second harmonic generation at 1550 nm wavelength in a thin film lithium niobate waveguide loaded with a silicon nitride strip.

February 21, 2019

Ryan Patton publishes research in Optics Letters

  • Ryan Patton and Ronald M. Reano, “Rotating polarization using Berry’s phase in asymmetric silicon strip waveguides,” Optics Letters 44, 1166-1169 (2019).
  • Abstract: Light propagating in an out-of-plane curvilinear waveguide acquires a Berry’s phase, which rotates optical polarization. The effect is promising for realizing waveguide polarization controllers. In high index contrast platforms, such as silicon-on-insulator, however, small waveguide cross-sectional asymmetries reduce the amount of polarization rotation. To overcome this, we present a method based on the periodic spatial modulation of Berry’s phase. Ninety degree polarization rotation is achieved, even in the presence of waveguide asymmetry. Using a numerical model based on Jones calculus, we demonstrate the approach with 303×300  nm squared asymmetric silicon waveguides. We convert polarization from transverse electric to transverse magnetic with a polarization extinction ratio (PER) greater than 20 dB PER over a 100 nm bandwidth in a 110×240 micrometer squared footprint.

February 3, 2019

Professor Reano gives invited talk at SPIE Photonics West in San Francisco, California

  • Ronald M. Reano, “Creating integrated optics with ion-sliced lithium niobate combined with patterned silicon or silicon nitride,” (Invited Paper) in Smart Photonic and Optoelectronic Integrated Circuits XXI, Paper 10922-25.
  • Abstract: Design, fabrication, and measurement aspects of integrated optic devices based on ion-sliced lithium niobate combined with patterned silicon or silicon nitride are presented. Two electro-optic devices are shown, namely, an RF electric-field sensor with a demonstrated sensitivity of 4.5 V/m per square root hertz and an electro-optic ring modulator with demonstrated digital modulation of 4.5 Gb/s. A device is also presented for quasi-phase matched second harmonic generation. Periodic poling of thin films of x-cut lithium niobate has been achieved with 7.5 micrometer poling period. Chip-scale electro-optics and nonlinear optics are envisioned for classical and quantum communications, sensing, and computing applications.

September 16, 2018

Ryan Patton presents at the Frontiers in Optics Conference in Washington DC

  • Ryan J. Patton and Ronald M. Reano, “Polarization rotation utilizing Berry’s phase in asymmetric silicon waveguides,” in Frontiers in Optics / Laser Science (FiO): 2018, OSA Technical Digest (online) (Optical Society of America, 2018), paper JW3A.2.
  • Abstract: We present a method to achieve polarization rotation in asymmetric silicon waveguides using Berry’s phase. By exploiting periodic in-plane and out-of-plane sections, we achieve 90° polarization rotation in the presence of linear birefringence.

July 25, 2018

Tyler Nagy presents at the Conference on Lasers and Electro-Optics in San Jose, California

  • Jonathan Tyler Nagy and R. M. Reano, “Periodic poling of ion-sliced x-cut magnesium oxide doped lithium niobate thin films,” in Conference on Lasers and Electro-Optics (CLEO): 2018, OSA Technical Digest (online) (Optical Society of America, 2018), paper SF2I.2.
  • Abstract: We fabricate and periodically pole 700 nm thick ion-sliced x-cut magnesium oxide doped lithium niobate thin films. Uniform domains with 50% duty cycle are imaged by piezo-response force microscopy.