Nanostructuring Optical Waveguides by Focused Ion Beam Milling. Near-Field Characterization.

Available online at http://www.kps.or.kr/home/kor/journal/library/search.asp?International audienceNanostructures have become an attractive subject due to many applications, particularly the photonic bandgap effect observed in photonic crystals. Nevertheless, the fabrication of such structures remains a challenge because of accurate requirement concerning regularity, shape, hole depth etc. of the structure. E-beam lithography permits a good control of dimensional parameters but needs a 1-step fabrication process. In our work, we have to combine traditional strip-load waveguides (SiO2/SiON/SiO2 on Si) and nanostructures whose dimension are totally different. This imposes a 2-step process where waveguides and nanostructures are successively fabricated. We have at our disposal different ways to characterize these nanostructures. A direct aspect control during and after FIB treatment can be achieved by FIB and SEM imaging. Scanning near-field optical microscopy (SNOM) is currently the most effective way to test guiding confinement in such surface structures by detecting the evanescent field

Nanostructuring lithium niobate substrates by focused ion beam milling

We report on two novel ways for patterning Lithium Niobate (LN) at submicronic scale by means of focused ion beam (FIB) bombardment. The first method consists of direct FIB milling on LiNbO3 and the second one is a combination of FIB milling on a deposited metallic layer and subsequent RIE (Reactive Ion Etching) etching. FIB images show in both cases homogeneous structures with well reproduced periodicity. These methods open the way to the fabrication of photonic crystals on LiNbO3 substrates

Technology and performances of silicon oxynitride waveguides for optomechanical sensors fabricated by plasma-enhanced chemical vapour deposition

The technology and performances of a micromachined channel waveguides, based on PECVD deposition of silicon oxynitride (SiOxNy) thin films, is presented. The deposition parameters of the PECVD process are studied in connection with their optical, mechanical and chemical properties. Waveguide deign is optimized allowing single mode, low loss propagation and high efficiency of coupling with single mode optical fiber. The proposed technology is applied to fabricate the pigtailed Mach-Zehnder interferometers, where the coupling from optical fiber to waveguide is based on the etch of U-grooves, supporting fibers in the same substrate as the waveguide substrate

A versatile and stable device allowing the efficient generation of beams with radial, azimuthal or hybrid polarizations

http://www.sciencedirect.com/A fiber device for the generation of annular beams with three symmetric polarization states is presented. Such a system requires only simple optical components and can be carried out in a very simple way. The high efficiency and stability of the system, as well as the remarkable purity of the polarization states so-created, are demonstrated through the results presented here

Generation of polychromatic radially and azimuthally polarized beams

International audienceWe propose a fiber-based system aimed at generating radially and azimuthally polarized beams over spectral ranges of several tens of nanometers. The device is either adaptable to polychromatic sources such as supercontinuum fiber lasers or to tunable ones (optical parametric oscillator, laser diode, etc.). A preliminary version of the system has been engineered to work in the visible portion of the spectrum. The concept proposed here can be adapted to the infrared or blue-UV spectral domains. As a starting application, polychromatic Bessel beams of the first order have been produce