David Pluchon

Light propagation in single mode polymer nanotubes integrated on photonic circuits

We report the theoretical and experimental study of photonic propagation in organic dielectric nanotubes elaborated by a wetting template method and showing off an aspect ratio as high as 200. Single mode behaviour is theoretically demonstrated without any cut-off conditions. Efficient evanescent coupling between polymer microstructures and nanotubes dispersed on a photonic chip as well as the high confinement and propagation in a single nanotube have been demonstrated. These results show the potential of well-defined one-dimensional nanostructures as building blocks for integrated organic photonic devices. Applications such as sensing and high speed communication are envisaged.

Investigation of fabrication and resonant optical coupling in various 2D micro-resonator structures in a UV210 polymer

In this paper, we report on the design and the overall realization of micro-resonators based on the development of adequate processes on a UV210 polymer. These micro-optical structures are developed by deep ultraviolet lithography allowing fabrication of nano-structured devices by means of low cost and reproducible processes. Two families of resonant micro-structures shaped on disk and stadium with various sizes are investigated. Structural and optical imaging characterizations have been carried out to ensure their ability to act as resonant integrated micro-structures. At first, scanning electron microscopy and Nomarsky microscopy studies confirm the UV-light process resolution down to 450 nm developed on a UV210 polymer. Then, optical characterizations have been performed as regards intensity and spectral properties of such micro-resonators. Field intensity measurements in visible and infrared ranges have been realized and validate light propagation by evanescent coupling between waveguides and micro-resonators. Finally, spectral analyses on TE modes demonstrate the presence of optical resonances with 1.45 nm and 2.19 nm free spectral range values for respectively disk and stadium micro-structures. The UV210 polymer appears appropriate for the realization of micro-structures requiring a few hundred nanometers gap-scale while maintaining adequate spectral properties for versatile applications in telecommunication and metrology.

Improvement of efficient coupling and optical resonances by using taper-waveguides coupled to cascade of UV210 polymer micro-resonators

In this paper, we report the overall design, fabrication and optical characterization of single and multiple resonant micro-structures patterned on the UV210 polymer and shaped by adequate deep-UV lithography procedures. Various families of ring and racetrack forms are investigated with different geometrical dimensions linked to the micro-resonators and the specific taper-waveguides and gaps allowing the optimized coupling. Well defined photonic structures families in the sub-micrometer range obtained by this deep UV-light process are clearly confirmed through scanning electron microscopy. In order to evaluate and quantify the efficiency of the sub-micrometer coupling, the recirculation of the light and the quality of the optical resonance aspects, a global study including top view intensity imaging, spectral measurements and Fast Fourier Transform analysis is performed for all these devices based on single and multiple family resonators. The experimental TE-mode resonance transmissions reveal a complete agreement with the period of the theoretically expected resonances. A maximum value of the quality factor Q = 3.5 x 10^3 at 1035 nm with a 3.2 times higher resonance contrast is assessed for cascade of triple micro-resonators respect to the photonic devices based on only one micro-resonator. In addition, these UV210 circuits made of specific tapers coupling to cascade loops act directly on the improvement of the evanescent coupling and resonances in terms of quality factor and extinction rate, by selecting successively and more precisely the optical mode resonance. All these designs and low cost technological reproducible steps, and furthermore the devices and protocol measurements are markedly suitable for mass fabrication and metrology applications.

From Fabrication to Characterization of 3D Organic Microresonators: A Complementary Alliance of Microfluidics and Optics

This paper introduces a preview of targeted current research on organic optofluidic materials and devices devoted to 3D photonics microresonators (MRs). First, such an approach takes advantage from a significant know-how on optical simulations of 3D spherical MRs by complementary and coupled ways based on electromagnetism and quantum mechanics principle. Such simulations have allowed to preset the quantization of whispering gallery modes (WGMs) and to define a new formulation of optical caustics in global 3D MRs cavities. Leaning from these simulations, an interdisciplinary approach has been achieved by combining microfluidics techniques and thin layer processes that allowed with flow rates control the realization of 3D droplets MRs of several tens of micrometers in radii. Finally, free-space optical characterizations have been performed on such 3D polymeric MRs by judicious protocols based, respectively, on a modified Raman spectroscopy laser excitation and an adequate direct beam waist optical coupling. Spectral analysis on such 3D MRs of various sizes confirms the excitation of the expected WGMs revealing free spectral range (FSR) and caustics values close to the analytical ones.

A novel deep-UV polymer for integrated photonics: from waveguides structures to taper-waveguides coupled to cascade of multistage resonators used as thermal sensors

An overview of current research on integrated photonics based on the new UV210 phot-oresist is given. We report the overall design, fabrication and characterization of waveguides structures, multistage microresonators and their potential as thermal sensors.

Investigation on 2D disks and stadiums micro-resonators structures based on UV210 polymer

In this paper, we report on the design and the overall realization of micro-resonators based on the development of adequate processes on UV210 polymer. These micro-optical structures are developed by deep ultraviolet lithography allowing fabrication of nano-structured devices by mean of low cost and reproducible processes. Resonant microstructures of disk and stadium shapes with various sizes were investigated. Structural and optical characterizations have been carried out to ensure their ability as integrated resonant micro-structures. At first, scanning electron microscopy studies confirm the UV-light process resolution down to 450 nm developed on UV210 polymer. Then, optical characterizations have been performed as regards spectral properties of such micro-resonators. Field intensity measurements in visible and infrared range have been realized and validate the aptitude of the micro-structures to propagate and to allow an evanescent photonic coupling between waveguides and micro-resonators. Finally, spectral analyses on TE modes demonstrate the presence of optical resonances associated to whispering gallery modes for disk structures and chaotic modes for stadium shapes. The UV210 polymer appears appropriate for the realization of microstructures requiring a few hundred nanometers gap-scale while maintaining adequate spectral properties for versatile applications in telecommunication and metrology.

Microfluidics and thin-film processes: a recipe for organic integrated photonics based on 3D microresonators

We report on the design and realization of photonic integrated devices based on 3D organic microresonators. This has been achieved by combining microfluidics techniques and thin-film processes. The microfluidic device and the control of the flow rates of the continuous and dispersed phases allow the fabrication of organic microresonators with diameter ranging from 30 to 200 μm. The resonance of the sphere in air has been first investigated by using the Raman spectroscopy set-up demonstrating the appropriate photonic properties. Then the microresonators have been integrated on an organic chip made of the photosensitive resin SU-8 and positioned at the extremity of a taper and alongside a rib waveguide. The realization of these structures by thin-film processes needs one step UV-lithography leading to 6μm width and 30μm height. Both devices have proved the efficient evanescent coupling leading to the excitation of the whispering gallery modes confined at the surface of the organic 3D microresonators. Finally, a band-stop filter has been used to detect the resonance spectra of the resonators once integrated.