Suppression of stimulated Brillouin scattering (SBS) in high power fiber amplifiers
AssigneeOFS Fitel, LLC
InventorsMarc Mermelstein, Andrew D. Yablon
Life of this patent
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Abstract
A fiber amplifier suitable for high power, narrow linewidth applications exhibits suppression of stimulated Brillouin scattering (SBS) by segmenting the fiber amplifier into separate portions that exhibit different Brillouin center frequencies. By changing the center frequencies in adjoining segments of the fiber amplifier, the backward-propagating Stokes signal is essentially blocked, and SBS is suppressed. In a preferred embodiment the segmentation is added to the terminating portion of the fiber amplifier. Various techniques, including temperature modifications, can be used to impart the desired center frequency shift.
Claims14
An optically-pumped fiber amplifier for suppressing stimulated Brillouin scattering (SBS) comprising
- an optical signal source;
- a section of fiber responsive to the optical signal source for amplifying an optical output signal therefrom, said section of fiber comprising at least two separate fiber segments disposed in series, each fiber segment formed to exhibit a different Brillouin center frequency, the Brillouin center frequencies being sufficiently different to prevent continuing Brillouin amplification in a backward-propagating Stokes signal passing from one fiber segment into an adjacent fiber segment of the fiber amplifier, reducing the total Stokes power generated in the fiber amplifier, wherein the at least two fiber segments comprise segments of different lengths disposed such that at least one fiber segment of shorter length is disposed at an output end of the optically-pumped fiber amplifier.
A method for suppressing Brillouin scattering in an optically pumped fiber amplifier comprising the steps of:
- providing an optical signal source;
- providing a section of optical fiber responsive to the optical signal source, the section of optical fiber comprising a plurality of separate fiber segments disposed in series, and
- configuring each fiber segment to exhibit a different Brillouin center frequency, the Brillouin center frequencies being sufficiently different to prevent continuing Brillouin amplification in a backward-propagating Stokes signal passing from one fiber segment into an adjacent fiber segment of the fiber amplifier, reducing the total Stokes power generated in the fiber amplifier, wherein the plurality of fiber segments comprise segments of different lengths disposed such that at least one fiber segment of shorter length is located at an output end of the fiber amplifier.
Dependencies are inferred from the claim text.