Abstract

The rising demand in ultrafast radiation sources has boosted the search for high power and high stability mode-locked fiber lasers, particularly at telecom wavelengths. In this work, we demonstrate the first ultrafast mode-locked fiber laser relying on InN as saturable absorber, centered at 1.5 μm. The saturable absorber consists of a 1-μm-thick InN grown on a GaN-on-sapphire template deposited by molecular-beam epitaxy [1], with a 250 nm-thick top layer of Al deposited by RF-sputtering. This material presents a very high nonlinear optical response, with a saturation fluence of F_sat=490 μJ/cm² and a large change in reflectance, of approximately the 100% [inset Fig. 1(a)]. It has been proved that the material can withstand extremely high fluences of 9000 μJ/cm² without suffering optical damage.

© 2017 IEEE