We review our recent work toward designing large mode area fibersfor high power applications. We show that appropriately designeddoped multi- mode fibers can be used to provide robust single-modeoutput when used in fiber laser cavities. Single-mode (SM) fiber modefield diameters of ~ 35 μm are demonstrated with record SM pulseenergies of 0.5 mJ at 1550 nm with a repetition rate of 200 Hz.Energies approaching 1 mJ are obtained with a slight compromise inmode quality. A modification in the laser cavity results in apassively modelocked laser giving femtosecond pulses with nanojouleenergies.
展开▼
