Abstract
The simultaneous production of both a 2-D waveguide and a Bragg grating is reported. The samples used consisted of a three layer slab structure produced by flame hydrolysis deposition. They were exposed to a focused KrF excimer laser beam. The exposure was done through a non-absorbing quartz plate which contained a 6 mm long phase mask with a period of 1066 nm on its central part. A type II grating was obtained, with the periodic perturbation clearly observed under a microscope.

Abstract
Flame hydrolysis deposited (FHD) silica waveguides are very important for use in planar lightwave circuits (PLC) because of their low loss and inherent compatibility with silica optical fibers. A low damage, anisotropic reactive ion etch process for the fabrication of single and multimode waveguides in silica for planar lightwave circuit applications is presented. The etch rate of the glass results in smooth sidewalls and deep anisotropic etching. Propagation losses and polarization sensitivity arising from the etch process are discussed.

Abstract
The hybrid sol-gel process is recognized to be an alternative route for production of low cost silica-based integrated optic devices, since it allows the elaboration of ridge waveguides without recourse to high cost processing, like ion etching. However, the high absorption of these materials in the NIR region (1300 and 1550 nm) has limited so far their use. The main objective of this article is to describe the major factors that lead to high losses in the final material and to give solutions to overcome this drawback. The choice of hybrid precursors and the influence of the experimental conditions of gel preparation are of paramount importance. Appropriate synthesis conditions allow a significant decrease of the gel losses (to 0,5 dB/cm) while keeping good wetability and UV-patternability. Each step of the waveguides elaboration was studied separately (UV-irradiation, etching, overcladding, storage) regarding the losses of the material. Post-baking of the waveguides is a way to significantly decrease the losses at 1550 nm. Under appropriate conditions, the losses measured in the waveguides can be kept below 1 dB/cm.

Abstract
Symmetric buried channel waveguides fabricated on silicon substrates by the organic-inorganic hybrid sol-gel process are reported. The buffer/cladding layer material is composed of methyl-modified silanes and presents high network flexibility and low refractive index, at low cost. Film thickness above 10 mum is possible without cracks, even after thermally baking the films at 150degreesC, and the refractive index is 1.468 at 632.8 nm. The influence of the methylsiloxane species on the material absorption loss was investigated, in particular at 1.55 mum. For channel waveguide core definition, a photopatternable layer was polymerised by 248 nm laser radiation through an amplitude mask, and the unexposed material was simply removed by an organic solvent. The transmission spectrum of the waveguides is presented and reveals an acceptable loss level of 0.3dB/cm at 1300 nm, but larger loss in the 1550 nm region. The procedure developed is compatible with optoelectronic integration in silicon.

Abstract
In this paper, direct UV-laser writing was used to produce channel waveguides and diffraction gratings on thin films of siliceous-based organic-inorganic hybrid materials. The optical quality of the films surface was studied by light scattering measurements. The produced Y-power splitters, optical filters and Fabry-Perot cavities were experimentally characterized for propagation in the near infrared spectral region.

Abstract
The symmetry of cladding modes excited in microbend and arc-induced long-period fiber gratings is investigated. An optimization technique is developed to determine the fiber parameters and to associate grating resonances with cladding modes of a particular symmetry. Using this optimization procedure, we show that the gratings induced in a standard fiber by arc discharges and microbends couple light to the antisymmetric cladding modes. In the case of a boron-germanium codoped fiber, the cladding modes excited by arc-induced gratings are found to be symmetric. Measurements of the near-field intensity distribution of cladding modes confirm the mode symmetry ascertained by the optimization technique. (c) 2006 Optical Society of America