Patent ID: 8089689

Claim:
A method comprising: providing a plurality of amplifying fiber segments including a first amplifying segment and a second amplifying segment, wherein the first amplifying segment has a core that has a first diameter, wherein the core of the first amplifying segment is surrounded by an inner cladding that is surrounded by an outer cladding, wherein the second amplifying segment has a core that has a second diameter, wherein the core of the second amplifying segment is surrounded by an inner cladding that is surrounded by an outer cladding, and wherein the first diameter is less than the second diameter; providing a connecting fiber segment, the connecting fiber segment having a core that includes a minimum-diameter core portion that has a third diameter, wherein the core of the connecting fiber segment is surrounded by a first cladding, and wherein the third diameter is less than the first diameter; fusing one end of the connecting fiber segment to an end of the first amplifying segment and fusing an opposite end of the connecting fiber segment to an end of the second amplifying segment, coupling pump light into the core of the first amplifying segment; coupling pump light into the core of the second amplifying segment; coupling signal light from the core of the first amplifying segment into the core of the connecting fiber segment and coupling signal light from the core of the connecting fiber segment into the core of the second amplifying segment; and amplifying the signal light in the first amplifying segment and in the second amplifying segment.