Femtosecond laser direct writing of evanescently-coupled planar waveguide laser arrays

We report on the fabrication of evanescently-coupled one-dimensional waveguide laser arrays in Nd:YAG crystals by employing femtosecond-laser direct writing (FsLDW). The far-field discrete diffraction patterns of fabricated waveguide arrays under a passive regime can be observed at the active regime. By adjusting the incoupling condition, diffraction patterns with different laser intensity distribution can be realized, which is also supported by our simulation. Results in this study suggest promising applications of such an active arrayed device for complex integrated photonic circuits.