Institut National D'optique

Sdl Inc.

Gilles Larose

Alain Chandonnet

Yves Painchaud

Robert Larose

Andre Fougeres

A laser to produce pulses of light having predetermined spectral shapes, comprising a waveguide, an optical pump source, a gain medium to produce seed radiation, and a modulator and an array of Bragg gratings to modify the properties of the seed radiation. Once generated by the gain medium, the seed radiation propagates in the waveguide where it is first pulsed by the modulator. The resulting pulses are then selectively reflected by the Bragg gratings, which separates different spectral components of the reflected beam. This reflected beam then travels back to the modulator, which is timed to let only the desired spectral components go through. In this manner the laser is self-seeded and allows spectrum and wavelength selection from pulse to pulse.

Wavelength sliced self-seeded pulsed laser

An optical device for modulating or interacting with radiation guided and propagating along an optical longitudinal axis of an optical waveguide, such as, an optical fiber, has a different directional geometry compared to conventionally comparable devices such as, for example, plasmon or planar surface modulators for optical fibers. The geometry includes a nonlinear, electro-optic medium formed between two spatially disposed electrodes. The medium/electrode sandwich is aligned along the waveguide longitudinal propagating axis and extends in a radial direction from the optical waveguide core with the inner end of the medium in spatial proximity to the waveguide core for evanescent coupling with the radiation field propagating in the waveguide. An applied electric field to the spatially disposed electrodes varies the refractive index of the electro-optic medium from just below the effective refractive index of the waveguide to just above the effective refractive index waveguide to induce a lossy condition on the propagating radiation. Modulation of the applied electric field will bring about intensity modulation of the propagating radiation.

Optical device employing edge-coupled waveguide geometry

A length of an optical fiber having a core and a surrounding cladding is held by a block with a portion of said length having substantially all of its cladding removed on one side of the portion and being exposed, and an index overlay perturbation pad is mounted near and substantially parallel to the portion. A translator moves the pad between a first position in which the pad is sufficiently remote from the portion to allow total internal reflection in the portion and a second position in which the pad is sufficiently close to the portion to allow light to escape from the core. The pad may be made of a metal for polarized modulation, or of a dielectric for unpolarized modulation. The optical switch provides very fast switching for a O-switched fiber laser.

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Gilles Larose