Acreo Ab

Telefonaktiebolaget Lm Ericsson (publ)

Ericsson Telecommunicacoes S.a.

Acreo Swedish Ict Ab

Rise Acreo Ab

Rise Research Institutes of Sweden Ab

Walter Margulis

Michael Fokine

Lars-Erik Nilsson

Leif Kjellberg

Åsa Claesson

Michael Lee Sundheimer

Pedro Torres

Hania Arsalane

Carmelo José Albanez Bastos-Filho

Joaquim Ferreira Martins-Filho

Mariana Torres Carvalho

Harald Knape

Anderson Stevens Leonidas Gomes

Daniele Seixas

Luciene Demenicis

Luiz Conrado

Maria Carvalho

Laurent Krummenacher

Azizahalhakim Sudirman

Niklas Myren

Asa Claerron

In one embodiment of the present invention, a method is disclosed of temporarily changing refractive index of an optical fiber containing a longitudinal electrode arranged in the cladding of said fiber along and parallel to the core of the fiber, wherein the change in refractive index is performed by applying a high voltage pulse to said longitudinal electrode, the high voltage pulse including a magnitude of at least 100 volts and a duration sufficiently short to prevent melting of the electrode, such that the electrode thermally expands through ohmic heating without melting and exerts a pressure on the fiber core to induce said temporary change of the refractive index. The method is suitably used for Q-switching a fiber laser.

Method for changing refractive index of an optical fiber by applying a high voltage pulse to a longitudinal electrode

A method of forming a longitudinal solid body within at least one longitudinal hole formed in an optical fiber, comprising the steps of placing a first end and a portion of the optical fiber in a heating chamber; keeping a second end of said optical fiber outside of the heating chamber; forcing a molten material into the longitudinal hole of the fiber from the first end; and thereupon longitudinally extracting the optical fiber from the heating chamber at a controlled rate. Preferably, the fiber is extracted while molten material is being urged into the fiber.

Method for forming a longitudinal solid body within an optical fiber

An impedance-matching coupler () comprises a dielectric substrate () onto which a conducting strip () is disposed. A dielectric layer (), preferably a dielectric film, is formed on top of the conducting strip and the first dielectric layer to encircle the conducting strip. A metallic layer () is finally provided on top of the dielectric layer. The dielectric layer has a dielectric constant that is substantially higher that the dielectric constant for the dielectric substrate, preferably more than ten times higher. A dielectric film with a thickness of less than 100 &#x3bc;m is advantageous, preferably between 5 and 100 &#x3bc;m, and even more preferably between 10 and 70 &#x3bc;m. The thickness of the dielectric substrate is preferably larger than for the dielectric film, preferably more than ten time larger. The conducting strip has preferably a constant width. The dielectric film thickness is preferably larger than 10% of the conducting strip width.

Impedance-matching coupler

An arrangement and method provide an optical thulium doped fiber amplifier utilizing a dual wavelength pumping scheme for amplifying an optical signal. The method includes the steps of: a first deposition (a) of energy into the fiber amplifier by pumping with radiation of a first wavelength; and a second deposition (b) of energy into the fiber amplifier by pumping with radiation of a second wavelength. The radiation of the first wavelength is arranged to induce, by single photon absorption, a population to theHlevel of the thulium dopant, and the radiation of the second wavelength primarily depopulates theFlevel, by excited absorption of a single photon, preferably by strong excited state absorption to theFlevel. The steps gives a population inversion between theHand theFlevels and facilitate a power efficient high gain amplification.

Dual-wavelength pumped thulium-doped optical fiber amplifier

The invention relates to a method and a device for controlling the refractive index in the core of an optical fiber. According to the invention, an optical fiber is provided with a longitudinal electrode running along the core of the fiber. An electric current is passed through the electrode to induce ohmic heating thereof, causing thermal expansion and consequently a compressing force upon the core of the fiber. This compression of the core leads to induced changes in the refractive index in the direction of the compressing force, and hence induces or alters birefringence in the core.

Method and device for controlling the refractive index in an optical fiber

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Huddinge, Sweden

Walter Margulis