Abstract
Hybrid materials produced by the hydrolytic sol-gel process reveal strong absorption in the spectral region of 1550 nm, mainly due to the high concentration of OH groups. This characteristic constitutes an obstacle to the application of these materials, in particular to telecom integrated optical devices. A simple thermal treatment applied to the device does not contribute to increase the transparency. The real-time influence of temperature and environment humidity on the optical transmission properties of sot-gel organic-inorganic raised channel waveguides is analyzed in order to achieve an understanding of the OH group's behaviour in the materials. We demonstrate that the level of the optical losses at 1550 nm can significantly be decreased at high temperature. Cooling the sample in dry atmosphere makes it possible to reach a better transparency, which can be useful to improve the performance of hybrid sol-gel optical devices.

Abstract
Hybrid sol-gel technology has proved its usefulness in the field of micro-optics. Indeed, it makes it possible to manufacture optical microcomponents by processes much simpler than those currently used, particularly when photopatternable materials are employed. However, for wavelengths in the near infrared window (NIR), this process is confronted with a major problem which results from the significant optical absorption of this type of materials, in particular around 1550 nm. The aim of this paper is to describe the origin of the losses of some hybrid sol-gel materials of direct interest in micro-device fabrication in order to propose solutions to achieve a greater transparency in the NIR region. The intrinsic absorption of the precursors was first of all considered since it is crucial to pursue the final goal of decreased losses. Then, the principal parameters of the sol-gel synthesis were studied. Among them, the thermal treatment conditions, the hydrolysis ratio and the controlled addition of transition metal alkoxides allow an improvement of the material transparency, at 1550 nm most particularly. This last point was considered with the highest attention, and NIR and NMR spectroscopies were employed to explain how the addition of zirconium alkoxides at the end of the reaction makes it possible to considerably decrease the losses in the material.

Abstract
We experimentally realized an integrated temporal Fourier transformer based on a linearly-chirped Bragg grating waveguide written in silica glass with a femtosecond laser. The device operates in reflection and has a 10-nm bandwidth. (C) 2010 Optical Society of America

Abstract
Integrated optics is a mature technology with standard applications to telecommunications. Since the pioneering work of Berger et al. 1999 beam combiners for optical interferometry have been built using this technology. Classical integrated optics device production is very expensive and time consuming. The rapid production of devices using hybrid sol-gel materials in conjunction with UV laser direct writing techniques allows overcoming these limitations. In this paper this technology is tested for astronomical applications. We report on the design, fabrication and characterization of multiaxial two beam combiners and a coaxial beam combiner for astronomical interferometry. Different multiaxial two beam combiner designs were tested and high contrast (better than 90%) was obtained with a 1.3 mu m laser diode and with an SLID (lambda(0) = 1.26 mu m, FWHM of 60 nm). High contrast fringes were produced with 1.3 mu m laser diode using the coaxial two beam combiner. These results show that hybrid sol-gel techniques produce devices with high quality, allowing the rapid prototyping of new designs and concepts for astronomy.

Abstract
Integrated optics is a well established technology that finds its main applications in the fields of optical communication and sensing. However, it is expanding into new areas, and in the last decade application in astronomical interferometry has been explored. In particular, several examples have been demonstrated in the areas of beam control and combination. In this paper, different examples of application integrated optics devices for fabrication of beam combiners for astronomical interferometry is given. For the multiaxial beam combiners, a UV laser direct writing unit is used for mask fabrication. The operation principles of the coaxial combiners fabricated in hybrid sol-gel were validated using an interferometric set-up. These results demonstrate that hybrid sol-gel technology can produce quality devices, opening the possibility of rapid prototyping of new designs and concepts.

Abstract
Femtosecond laser fabrication of optical waveguides in bulk silica glass is extended to integrated optical waveplates. Polarization retardation was controlled by laser exposure, providing for trimming of waveguide birefringence between 10(-5) and 10(-4).