Session 4 | Passive Components / Devices

Waveguide coupled high-Q micro-optical resonators

Simone BERNESCHI1, Immacolata Angelica GRIMALDI2, Silvia SORIA1, Romeo BERNINI2, Gualtiero NUNZI CONTI1
1Institute of Applied Physics “N. Carrara”,CNR-IFAC, Via Madonna del Piano 10, 50019 Sesto Fiorentino (FI), Italy
2Institute for Electromagnetic Sensing of the Environment, CNR-IREA, Via Diocleziano 328, 80124 Napoli, Italy

For practical applications, in order to fully exploit the unique properties of Whispering Gallery Mode (W/M) micro-optical resonators, a critical point is an efficient and robust coupling of the light to the cavity [1,2]. We present the results of our studies on coupling methods based on integrated waveguides, with particular reference to the case of crystalline waveguides (LiNbO3) and polymeric waveguides (SU8 photoresist). In both cases the W/M resonators were made of the same material of the waveguides and Fig. 1 shows pictures of the two systems with a LiNbO3 disk (Fig. 1a), and a SU8 bottle resonator (Fig. 1b).


Highly-Efficient Subwavelength Engineered Grating Couplers for Silicon-on-Insulator Waveguides

D. Benedikovic1,*, C. Alonso-Ramos1, P. Cheben2, J.H. Schmid2, S. Wang2, D.-X. Xu2, R. Halir3, A. Ortega-Moñux3, L. Vivien1, J. Lapointe2, S. Janz2, J.-G. WangüemertPérez3, I. Molina-Fernández3, J.-M. Fédéli4, and M. Dado5
1Institut d’Electronique Fondamentale, Université Paris Sud, CNRS, UMR 8622, Université ParisSaclay, Bat. 220, Orsay Cedex, France
2National Research Council Canada, 1200 Montreal Road, Ottawa, Canada
3 Universidad de Málaga, Dpto. de Ingeniería Comunicaciones, 29010 Málaga, Spain
4CEA-LETI, Minatec, CEA-Grenoble, 38054 Grenoble, France
5University of Žilina, Dept. of Telecommunications and Multimedia, 010 26 Žilina, Slovakia

Abstract: We present experimental results of efficient subwavelength index engineered surface grating couplers, developed in a standard 220-nm SOI substrate. Grating couplers are fabricated using a single full etch or a dual etch process (full etch and 70nm shallow etch). The measured efficiency of -2.2 dB, -2.5 dB, and -0.7 dB are reported for single-etch couplers without and with metal reflector in the near-IR wavelengths. We demonstrate a peak coupling efficiency of -1.3 dB for a novel and flexible dual-etch grating coupler with interleaved deep and shallow etched trenches.


Optical frequency domain reflectometry for characterization of waveguide crossings

Dan ZHAO1*, Dzmitry PUSTAKHOD1, Luc AUGUSTIN1,2, Kevin WILLIAMS1 and Xaveer LEIJTENS1
1Eindhoven University of Technology, Den Dolech 2, 5612 AZ, Eindhoven, the Netherlands
2Smart Photonics, Horsten 1, 5612 AX, Eindhoven, the Netherlands

Abstract: We have analysed crossings of shallow etched waveguides with a selfcalibration high-accuracy optical frequency domain reflectometry method. The power reflection coefficient of crossings was measured to be 1.4(0.6∙103.


Highly efficient nonlinear waveguides in LiNbO3 fabricated by a combination of Soft Proton Exchange (SPE) and E-beam writing.

Maxim NERADOVSKIY1,3*, Dmitry CHEZGANOV1,2, Lubov GIMADEEVA1, Evgenii VLASOV1, Vsevolod KVASHNIN1, Elizaveta KOLCHINA1, Andrey AKHMATKHANOV1,2, Maria CHUVAKOVA1, Denis ALIKIN1, Herve TRONCHE3, Florent DOUTRE3, Pascal BALDI3, Vladimir Ya. SHUR1,2, Marc P. DE MICHELI3
1Institute of Natural Sciences, Ural Federal University, 620000, Ekaterinburg, Russia
2Labfer Ltd., 620014, Ekaterinburg, Russia, 3LPMC, University of Nice Sophia-Antipolis, 06100 Nice, France

Using an E-Beam writing process we produced high quality periodical domains in SPE lithium niobate waveguides. In SHG experiment we got up to 47%W.cm2 conversion efficiency which is comparable to similar waveguides where the domains are obtained by other techniques.


Proposal of Optical Thresholder Consisting of Two MZIs with Nonlinear Micro-Ring Resonator

Tadashi KONDO1, Hiroki KISHIKAWA1*, Nobuo GOTO1, Srinivas TALABATTULA2
1 Tokushima University, Tokushima 770-8506, Japan
2 Indian Institute of Science, Bangalore 560-012, India

We propose a novel optical thresholder having a flat power transfer function both in low-level and high-level output. Fig. 1 shows a configuration of the optical thresholder consisting of a single MZI with a ring resonator in the upper arm and a phase shifter in the lower arm. The bar path coupling coefficient of optical electric fields between the straight waveguide and the ring waveguide is denoted by Z[. The phase shifter is used to adjust the thresholding characteristics. A similar structure but without the phase shifter in the lower arm was reported by Heebner and Boyd [1]. A fraction of the field through the upper arm is coupled to the ring waveguide and circularly propagates along the ring. The transfer function of optical electric fields through the ring resonator is derived as