Fabrication and optical characterization of pedestal micro-structures on DUV210 polymer: waveguides structures towards micro-resonators

¹ Institut de Physique, Université de Rennes, 1, IPR CNRS 6251, 35042 Rennes, France
² Institut d’Electronique et de Télécommunications, Université de Rennes, 1, IETR CNRS 6164, 35042 Rennes, France

^a e-mail: bruno.beche@univ-rennes1.fr

Received: 13 April 2015
Revised: 26 May 2015
Accepted: 8 June 2015
Published online: 7 July 2015

Abstract

The paper presents the global design, fabrication and optical characterizations of pedestal waveguides and 2D microresonators (MRs) made of DUV210 polymer. These particular geometries are achieved thanks to specific deep-UV lithography procedures allowing sub-lambda development coupled to chemical etching able to shape such pedestal configuration on various optical microstructures. Scanning electron microscopy images have confirmed their features. Moreover, such families of pedestal structures were characterized experimentally, including the optical losses measurements for the waveguides and the optical resonance responses for two kinds of microresonators. Optical studies of single mode propagation losses measurements have been performed by a cut back method leading to values close to 20 dB/cm at a 635 nm wavelength. Additionally, resonant spectral analysis has been performed into pedestal rings and racetracks microresonators with a broadband laser source centered at 795 nm, demonstrating the presence of expected theoretical resonances. Free spectral range (FSR) values of 2.8 nm and 2.51 nm have been measured for these new designed pedestal resonators on DUV210 related to quality factor values superior to 520 and 610 respectively.