Cascaded self-induced holography: a new fabrication technology for optoelectronics

We present a new method of fabricating submicron gratings with a high filling factor for optoelectronic devices from a glass mask. The glass mask has gratings on both sides with a period of at least four times of the final feature size. By modifying the grating periods on both sides of the glass mask, one can achieve multiple-period gratings with a very fine period spacing for advanced wavelength division multiplexing (WDM) devices. In this paper, we demonstrate 0.5 μm second-order gratings for 1.55 μm distributed feedback (DFB) lasers and gratings with a 6 Å period difference for WDM laser arrays using only optical sources