<title>Novel VCSEL-based smart pixel for high-contrast, high-gain, and high-speed optical switching</title>

Abstract

We present a novel smart pixel composed of an optoelectronic threshold switch with gain and a vertical cavity surface-emitting laser (VCSEL). In this smart pixel two surface-normal input optical beams control an output optical beam emitted by the VCSEL. In its present hybrid version the VCSEL-based smart pixel is capable of opto-optical switching with an output contrast ratio in excess of 30 dB at an optical power of about 1.5 mW. For quasi-stationary operation we achieve an optical gain of up to 3 X 10<SUP>5</SUP>. We also report drastic improvements on the switching dynamics. Operating the receiver with an optical input power of 130 (mu) W we achieve bitrates of up to 160 Mbit/s and an optical gain of 11, while optical inputs of 410 (mu) W result in a maximum bitrate of 400 Mbit/s and an optical gain of 3.6. The minimum input optical energy required for switching is 765 fJ, the AC output contrast ratio is 9 dB. Optically performed NAND and NOR logic operations are demonstrated at 40 Mbit/s with a fan-out of 7.6. We further show that the functionality of this smart pixel can easily be extended to electric read-out of input optical data and to direct electric control of the VCSEL within the smart pixel configuration. In particular, we demonstrate conversion of electric input to optical output data at 1 Gbit/s.