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Title: Vertical coupling of laser glass microspheres to buried silicon nitride ellipses and waveguides

We demonstrate the integration of Nd{sup 3+} doped barium-titanium-silicate microsphere lasers with a silicon nitride photonic platform. Devices with two different geometrical configurations for extracting the laser light to buried waveguides have been fabricated and characterized. The first configuration relies on a standard coupling scheme, where the microspheres are placed over strip waveguides. The second is based on a buried elliptical geometry whose working principle is that of an elliptical mirror. In the latter case, the input of a strip waveguide is placed on one focus of the ellipse, while a lasing microsphere is placed on top of the other focus. The fabricated elliptical geometry (ellipticity = 0.9) presents a light collecting capacity that is 50% greater than that of the standard waveguide coupling configuration and could be further improved by increasing the ellipticity. Moreover, since the dimensions of the spheres are much smaller than those of the ellipses, surface planarization is not required. On the contrary, we show that the absence of a planarization step strongly damages the microsphere lasing performance in the standard configuration.
Authors:
 [1] ; ; ;  [2] ;  [3] ;  [4]
  1. NEST, Istituto Nanoscienze—CNR and Scuola Normale Superiore, Piazza San Silvestro 12, Pisa I-56127 (Italy)
  2. Departament d'Electrònica, Universitat de Barcelona, Barcelona 08028 (Spain)
  3. Depto. Física, Universidad de la Laguna, 38206, La Laguna (Spain)
  4. NEST, Istituto Nanoscienze and Dipartimento di Fisica, Università di Pisa, Largo Pontecorvo 3, Pisa I-56127 (Italy)
Publication Date:
OSTI Identifier:
22494819
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 118; Journal Issue: 9; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; BARIUM SILICATES; CONFIGURATION; DOPED MATERIALS; LASER RADIATION; MICROSPHERES; MIRRORS; NEODYMIUM IONS; SILICON NITRIDES; SPHERES; SURFACES; TITANIUM SILICATES; VISIBLE RADIATION; WAVEGUIDES