Abstract

Recently the use of nonresonant nonlinearity for mode locking of the solid-state lasers has gained a great attention in the literature.¹-³ Many types of the lasers have been mode locked successfully using the self-phase modulation (SPM) in the additional cavity, the nonlinear optical Kerr effect and Kerr self-focusing. The main principle of these systems is the transformation of the nonlinear phase perturbation due to three-order nonlinearity to the amplitude modulation. Most recently publication reports on a new mode locking mechanism demonstrated in Nd:glass laser yielding a stable train of 129 fs pulses.⁴ The main idea of this mechanism is the combined action of linear frequency shift introduced by long- pass wavelength filter and nonlinear frequency shift owing to SPM.

© 1995 IEEE