A multimode optical amplifying fiber with a transversely coupled optical pumping beam
OwnerFrancois Boubal, Paul Salet +2inventors
InventorsFrancois Boubal, Paul Salet, Mauro Bettiati, Gerard Gelly
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Abstract
The invention relates to an optical amplifier (3) in which a source beam (1) and a pumping beam (2) are coupled. The pumping beam (P) is introduced into the fibre (3) laterally with respect to the optical axis (5) of the fibre, and focused by the curvature of the fibre (3) on a mirror (6) formed by a polished end face (8) so as to deflect it inside a numerical aperture cone of the optical fibre (3).
Claims8
An optical amplifier comprising an amplifying fibre (3) associated with a laser source (2) emitting an optical pumping beam towards the fibre, characterised in that the pumping beam (P) is introduced into the fibre (3) laterally with respect to the optical axis (5) of the fibre, and in that the fibre (3) comprises a mirror (6) formed by an end face (8) polished so as to deflect the pumping beam (P) inside a numerical aperture cone of the optical fibre (3).
An optical amplifier according to either one of the preceding claims, characterised in that the pumping beam (P) with an elliptical cross-section issuing from the laser (2) is transformed by the curvature of the optical fibre (3) into a beam internal to the said fibre (3) having a substantially circular cross-section.
An optical amplifier according to one of the preceding claims, characterised in that the polishing angle θ of the mirror (6) of the end face (8) of the fibre (3) is greater than the total angle of reflection.
An optical amplifier according to any one of the preceding claims, characterised in that the pumping beam (P) is introduced into the optical fibre (3) with an angle of incidence β of 90°, the end face (8) of the fibre (3) being polished as a mirror (6) with a polishing angle θ of 45°.
An optical amplifier according to any one of the preceding claims, characterised in that the end face (8) is partially polished in order to constitute a mirror (6), the other portion of the end face (8) of the fibre (3) being perpendicular to the optical axis (5) so as to introduce the source beam (1) in line with the optical axis (5).
Dependencies are inferred from the claim text.