Femtosecond passively mode-locked Ti:Al_2O_3 laser with a nonlinear external cavity

Abstract

Ultrashort pulses are generated in a Ti:Al(2)O(3) laser by using a coupled nonlinear external cavity. The external cavity uses self-phase modulation in an optical fiber to achieve passive mode locking without the need for synchronous pumping or acousto-optic modulation. A stable train of chirped 1.4-psec pulses is generated. After dispersive compensation, pulses as short as 200 fsec are obtained.