Abstract

Optical-differentiator operation was observed by using only a short-period super-lattice (SPSL) having the Wannier-Stark localization (WSL) effect ^1,2 The p-i-n-diode sample had 100 periods of a nominally undoped GaAs/AlAs (42.5 and 8.5-Å-thick) super-lattice layer cladded by 50-nm Al_0.4Ga_0.6As undoped layers, and the GaAs substrate underneath the optical window was etched off to fabricate a transmission device. The incident light from a cw Ti:sapphire laser was modulated by an acousto-optical modulator (AOM) whose duty ratio was reduced to 10⁻² −10⁻⁴ to avoid thermal effects. The incident-beam diameter monitored with a microscope setup was about 4 μm.

© 1995 Optical Society of America