Paul Grenier

Velocity measurements comparison of water and pentane travelling in capillary optical fibers coated respectively with a xerogel and a poly(dimethylsiloxane) absorbing layer

An analysis of the optical signal transmitted by a polarimetric sensor developed for the measurement of velocities of fluids in a capillary optical fiber is presented. It allows one to determine whether a fluid is moving in the vapor or the liquid phase.

Laser beam transformation technique for high-power laser diode linear arrays

This paper reports on a novel pair of microlens arrays (MLAs) for efficient coupling of the high aspect ratio optical beam emitted by high-power laser diode linear arrays (also referred to as laser diode bars) into the core of multimode optical fibers. These novel MLAs overcome the limitations observed when using high fill factors laser diode bars. The MLA designs are described. Results from modelling work show good coupling performances for laser diode bars with fill factors up to 75%. The technique for fabricating the complex surface profiles of the MLAs is discussed. Masters are first fabricated and MLAs are then replicated, so that volume production at low cost can be envisioned. The fabricated MLAs have been used for reshaping and fiber coupling the output of a 10-mm laser diode bar. An efficiency of 74% has been obtained when coupling into an optical fiber having a core diameter of 400 μm and a numerical aperture of 0.22.

Laser-diode array collimation for scene illumination purposes

During the last five years, INO has conducted a program to develop high performance diode laser illuminator for ATV (active TV) system. Illuminator made using INO proprietary collimating method, which uses GRIN (mu) -lenses for the fast axis and plano-convex (mu) -lenses for the slow axis, were found to provide uniform and tightly collimated beam, diffraction-limited for the fast axis. Such collimated laser diode arrays were proven to efficiently illuminate non- cooperative scene at 1 km with only 6 W of average power.