Alcatel

Catherine Martinelli

Christian Simonneau

Lionel Provost

Dominique Annie Mongardien

Florence Leplingard

Ekaterina Bourova

Dominique Bayart

Carlos Luis De Barros

Emmanuel Desurvire

Olivier Leclerc

Sophie Borne

Thierry Lopez

Frédéric Seguineau

Thibaut Sylvestre

Frédérique Vanholsbeeck

Phillippe Emplit

The amplifying optical fiber comprises a single-mode core and a multimode core surrounding the single-mode core, the multimode core containing a doped layer referred to as a 'doped ring' and having a certain concentration of active rare earth ions to perform amplification by active rare earth ions on at least one optical signal for injection into the amplifying fiber. The fiber is dimensioned so that the product of its length multiplied by its Raman efficiency is greater than or equal to 0.5 W. In addition, the fiber presents absorption defined by an absorption coefficient expressed in dB/m, which absorption presents, at a certain wavelength, a maximum value referred to as the 'absorption maximum', the fiber presents accumulated absorption, corresponding to the product of its length multiplied by the absorption maximum, that is greater than or equal to 100 dB. The invention also provides an amplifier including such a fiber, a single-mode pump, and a multimode pump.

Doped-ring amplifying optical fiber, and an amplifier containing such a fiber

The amplifying optical fiber () comprises a single-mode core () and a multimode core () surrounding the single-mode core, the multimode core containing a doped layer referred to as a 'doped ring' () and having a certain concentration of active rare earth ions () to perform amplification by active rare earth ions on at least one optical signal for injection into the amplifying fiber. The fiber is dimensioned so that the product of its length multiplied by its Raman efficiency is greater than or equal to 0.5 W. In addition, the fiber presents absorption defined by an absorption coefficient expressed in dB/m, which absorption presents, at a certain wavelength, a maximum value referred to as the 'absorption maximum', the fiber presents accumulated absorption, corresponding to the product of its length multiplied by the absorption maximum, that is greater than or equal to 100 dB. The invention also provides an amplifier including such a fiber, a single-mode pump, and a multimode pump.

A method for remodulation of a modulated optical signal is disclosed which uses a disturbed line signal and an optical clock signal derived from the undisturbed original line signal modulated with the bitrate frequency feeding both signals in a Raman amplifying fiber connected to at least one Raman pump running the clock signal as Raman pump wavelength for the line signal.

Method for remodulation of a modulated optical signal and device for remodulation and transmission system

It is disclosed a pump energy source () for providing pump energy (E_p) to an optical transmission system () transmitting an optical signal along an optical fiber, in particular an optical transmission system () in which a beam of said pump energy (E_p) is introduced to said optical fiber so that said beam of said pump energy (E_p) copropagates with said optical signal.

Pump energy source, method of providing pump energy to an optical transmission system, and optical transmission system

Disclosed is a Raman laser device () having a first cavity in which lasing occurs at a first frequency, and at least one second cavity in which lasing occurs at a second frequency. Thereby respective first and second waves inside the respective cavities are generated having a first power and a second power, respectively. Further, beams propagating outside the cavities are generated by coupling out a part of the first power and a part of the second power utilizing respective output mirrors. The part of the second power that is coupled out is attenuated without attenuating the complementary part of the second power remaining in the second cavity. The Raman laser device is characterized in that the part of the second power that is coupled out is attenuated utilizing at least one Fiber Bragg Grating ().

Multiple output Raman fiber laser with stable and small output power for seed applications

The invention is dealing with a Raman amplifying device comprising an optical path, pump sources for generating a plurality of Raman pump signals and means for coupling the plurality of Raman pump signals into the optical path for backward pumping. The plurality of optical Raman pump signals are time-division multiplexed by multiplexing controlling means and the controlling means apply a modulation frequency beyond the corner frequency of the co-propagating modulation transfer function. The method to modulate the time division multiplexed Raman signal gives a condition to avoid the increase of double Rayleigh scattering noise.

Raman amplifying device and method for pump modulation

A Raman amplifier () including at least one amplifying fiber () and a coupler () for coupling at least first () and second () pump laser modules to the amplifying fiber (), the first pump laser module () including a frequency discriminator () for selecting an optical frequency to be emitted with an optical power exceeding an optical power of remaining optical frequencies that are also emitted by the first pump laser module (). The first optical frequency is spaced apart from a local maximum () in optical power of the remaining optical frequencies, and the second pump laser module () emits at an optical frequency one Stokes-frequency above the frequency of the local maximum (). The first optical frequency and the frequency of the local maximum are chosen on Stokes-frequency above the signal frequency range. As a consequence, the Raman gain provided in the Raman amplifying fiberis broadened.

Raman amplifier and method for pumping a Raman amplifier

A cascaded Raman laser () has a pump radiation source () emitting at a pump wavelength &#x3bb;, an input section () and an output section () made of an optical medium. Each section () comprises wavelength selectors (and) for wavelengths &#x3bb;, &#x3bb;, . . . , &#x3bb;, where n&#x2267;3, &#x3bb;&#x3c;&#x3bb;&#x3c;&#x3bb;&#x3c; . . . &#x3c;&#x3bb;&#x3c;&#x3bb;and &#x3bb;, &#x3bb;, . . . , &#x3bb;being k&#x2267;1 emitting wavelengths of the laser (). The laser further comprises an intracavity section () that is made of a non-linear optical medium, has a zero-dispersion wavelength &#x3bb;and is disposed between the input () and the output () section. The wavelengths &#x3bb;, &#x3bb;, . . . , &#x3bb;of the wavelength selectors (and) and the zero-dispersion wavelength &#x3bb;of the intracavity section () are chosen such that energy is transferred between different wavelengths by multi-wave mixing.

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Palaiseau, France

Catherine Martinelli