Patent ID: 7768700

Claim:
A method comprising: providing a plurality of amplifying fiber segments including a first segment and a second segment that are joined to one another at a junction, wherein the first segment has a core that is surrounded by an inner cladding that has a first diameter, wherein the inner cladding of the first segment is surrounded by an outer cladding, wherein the second segment has a core that is surrounded by an inner cladding that has a second diameter, wherein the inner cladding of the second segment is surrounded by an outer cladding, and wherein the second diameter is different than the first diameter; coupling pump light into the core of the first segment and into the core of the second segment; coupling signal light from the core of the first segment into the core of the second segment; and amplifying the signal light in the first segment and in the second segment, wherein a wavelength shift of a non-linear frequency-shifted characteristic of the first segment is not equal to a wavelength shift of the non-linear frequency-shifted characteristic of the second segment.