US 2003/0169489 A1 · Multi-mode erbium micro fiber amplifier (EMFA)

Abstract

A compact, low-cost mid-gain Erbium Micro-Fiber Amplifier (EMFA) is provided by multi-mode pumping a micro fiber formed from a specialty multi-component glass and highly co-doped with Er:Yb. The specialty glass exhibits a much higher core absorption coefficient than standard glasses. As a result, the lower order modes are rapidly absorbed in the fiber core. The abrupt change in the mode profile perturbs the higher order modes and mode couples them into the lower order modes within a very short length of fiber, less than 20 cm. This “absorptive mode coupling” effect can double the absorption efficiency of a circular symmetric micro fiber and extend the length over which such a highly doped fiber can be efficiently inverted. The combination of multi-mode pumping with short fiber lengths reduces the form factor and cost of EMFAs.

Claims29

Dependent claims

An optical fiber amplifier, comprising:

A micro fiber of length L less than 20 cm coupled between lengths of single-mode fiber to receive and amplify an optical signal, said micro fiber having a core and an inner cladding of similar multi-component glass compositions with said core being co-doped with 0.5-5 wt. % erbium and 5-30 wt. % ytterbium;
and
A multi-mode pump laser that emits pump radiation that is coupled into the micro fiber's inner cladding and is partially absorbed by the doped core causing stimulated emission and amplification of the optical signal.

Dependencies are inferred from the claim text.

Multi-mode erbium micro fiber amplifier (EMFA)

Life of this patent

Multi-mode erbium micro fiber amplifier (EMFA)

Life of this patent

Abstract

Claims29