Nkt Photonics A/s

Lucent Tech, Denmark

Ionas A/a

Poul Varming

Jens Engholm Pedersen

Christian V Poulsen

Henrik Sørensen

Thomas O Fagerhøj

Bjarke Gøth

Bera Palsdottir

Bjarke Goth

Martin Kristensen

Thomas O Fagerhoj

Henrik Sorensen

Jorg Hubner

Milan Sejka

A laser device includes a laser configured to generate laser light and a laser control module configured to receive at least a portion of the laser light generated by the laser, to generate a control signal and to feed the control signal back to the laser for stabilizing the frequency, wherein the laser control module includes a tunable frequency discriminating element which is preferably continuously frequency tunable, and where the laser control module is placed outside the laser cavity.

Laser device

A laser device includes a tunable laser having a laser cavity and a laser control module placed outside the laser cavity, the tunable laser being configured to generate laser light having a center frequency, the laser control module being configured to receive at least a portion of the laser light generated by the laser, to generate a control signal and to feed the control signal back to the laser for stabilizing the frequency, wherein the laser control module includes an interferometer having interferometer mirrors and a tunable interferometer length, and wherein the interferometer length is tunable by an actuator arranged between the interferometer mirrors and by thermal variation.

The invention relates to a laser device, comprising a laser configured to generate laser light and a laser control module configured to receive at least a portion of the laser light generated by the laser, to generate a control signal and to feed the control signal back to the laser for stabilizing the frequency, wherein the laser control module comprises a tunable frequency discriminating element which is preferably continuously frequency tunable, and where the laser control module is placed outside the laser cavity.

Refractive index modifications such as e.g. Fiber Bragg gratings in micro-structured Fiber are according to an aspect of the invention fabricated by first filling and/or purging the holes of the micro-structured fiber with inert gas or by evacuation and, optionally subsequently scaling the ends. Alternatively, the ends of the micro-structured fiber may be sealed without a preceding purging or evacuation of the holes. In this way hydrogen or deuterium present in the holes after photosensitizing loading will not react with atmospheric oxygen to form water. Water formed this way would otherwise seriously impair the grating formation process. Bragg gratings and other refractive index structures can thus be fabricated with high quality and predictable specifications in micro-structured fiber. Sealing the fiber ends also prevents in-diffusion of moisture. The invention may e.g. find application in connection with fiber optical sensors, high-power fiber lasers, etc.

Method of inducing refractive index structures in a micro-structured fiber, a micro-structured fiber and an article

A method of producing an active optical waveguide having asymmetric polarization, said method comprising the steps of (a) providing an active optical waveguide (10) comprising: (i) a transverse refractive index profile (21) comprising a guiding region (11), an intermediate region (13), and a non-guiding region (12); (ii) a transverse photorefractive dopant profile (31) comprising a constant or graded photorefractive dopant concentration within at least one of the guiding, non-guiding and intermediate regions, except that the photorefractive dopant is not located solely in the guiding region; and (iii) exhibiting in said guiding region, intermediate region, or both, light guiding modes having different polarizations; and (b) exposing at least a part (10a, 10b) of the active optical waveguide to an effective transverse illumination of light (20) reacting with the photorefractive dopant and modifying said transverse refractive index profile; said part of the active optical waveguide being exposed to a fluence selectively suppressing the propagation of the light guiding modes having different polarizations so that the propagation of one mode is less suppressed than the propagation of the other mode(s). Such an active optical waveguide, single polarization mode optical waveguide lasers and multi-wavelength single polarization mode optical waveguide lasers comprising such an active optical waveguide, methods of their production, and their uses in telecommunications, in spectroscopy, in sensors and in absolute calibrated laser light sources.

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Copenhagen, Denmark

Poul Varming