Abstract

Femtosecond pulses have been generated in erbium doped fibre lasers using a number of different cavity designs and mode-locking techniques. These have proven capable of directly generating pulses as short as 98 fs at 1.55 μm¹, the lowest loss "window" in optical fibre used for telecommunications. A second low loss window exists at 1.3 μm and recently considerable interest has been directed towards Praseodymium (Pr³⁺) doped fluoride fibre as an amplifier providing gain at this wavelength. Pr³⁺ doped into a fluoride glass host high gain over a range of ~50 nm and this broad bandwidth has the potential to support femtosecond pulses.

© 1994 Optical Society of America