Low power, high speed, all-optical logic gates based on optical bistability in graphene-containing compact microdisk resonators
Peyman Keshtkar, Mehdi Miri, Navid Yasrebi
Abstract
CMOS-compatible all-optical logic gates based on optical bistability are designed and numerically characterized. For this, graphene and H-BN-based hybrid plasmonic microdisk/waveguide structures have been used to achieve optical bistability at very low threshold power and with small dimensions. The simulation results and coupled-mode theory calculations show that, by adjusting the radius of the microdisk resonator, the threshold power and response time of the optical bistability can be tuned in a wide range. It is shown that bistable devices with overall dimensions of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mn>2</mml:mn> </mml:mrow> <mml:mspace width="thickmathspace"/> <mml:mtext>µ</mml:mtext> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="normal">m</mml:mi> </mml:mrow> <mml:mo>×</mml:mo> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mn>2.2</mml:mn> </mml:mrow> <mml:mspace width="thickmathspace"/> <mml:mtext>µ</mml:mtext> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="normal">m</mml:mi> </mml:mrow> </mml:math> can easily be designed having either threshold powers as low as 0.79 µW (microdisk radius of 0.92 µm) or very short fall time and rise times of 1.24 and 1.53 ps (microdisk radius of 0.93 µm). The design procedure for the AND, NAND, OR, NOR, and NOT logic gates is discussed. Simulation results show that the proposed logic gates have much smaller footprints, lower power consumption, and higher speeds with acceptable response time, compared with the previously reported structures.