Experimental realization of an optical digital comparator using silicon microring resonators

Abstract

We propose and experimentally demonstrate a silicon photonic circuit that can perform the comparison operation of two-bit digital signals based on microring resonators (MRRs). Two binary electrical signals regarded as two operands of desired comparison digital signals are applied to three MRRs to modulate their resonances through the microheaters fabricated on the top of MRRs, respectively (here, one binary electrical signal is applied to two MRRs by a 1×2 electrical power splitter, which means that the two MRRs are modulated by the same binary electrical signal). The comparison results of two binary electrical signals can be obtained at two output ports in the form of light. The proposed device is fabricated on a silicon-on-insulator substrate using the complementary metal-oxide-semiconductor fabrication process, and the dynamic characterization of the device with the operation speed of 10 kbps is demonstrated successfully.

Recent advances in integrated optical directed logic operations for high performance optical computing: a review

“…However, unlike electrical circuits, optical combinational logic functions are usually implemented by an entire optical switching network directly in optical DL [14], thus does not lead to delay accumulation. Various combinational DL operations have been demonstrated [73][74][75][76][77][78][79][80][81][82][83][84] and recent publications are to be introduced in this sub-section.…”

“…Subsequently, a circuit was demonstrated to perform half-subtracting operation [79]. Other important combinational DL devices, including the comparator [80][81][82], parity checker [83], and Feynman gate [84] were also demonstrated with relatively low working speed for proofs of concepts in recent years. To achieve higher operational speeds, one can employ other advanced modulation schemes, such as the plasma dispersion effect [85,86], graphene-based Fermi level modulation [87][88][89], or lithium niobate waveguide [90][91][92] to modulate the MRRs.…”

Design of All-Optical Subtractors Utilized with Plasmonic Ring Resonators for Optical Computing

“…Firstly, researchers designed and manufactured optical devices to implement directed logic gates, such as AND/NAND, OR/NOR, and XOR/XNOR [22][23][24]. Then, more complex optical devices were proposed to realize computing functions such as full-addition, numeric compare, and matrix-vector multiplication [25][26][27][28][29]. However, such optical devices based on a DL mechanism are almost always realized on a siliconon-insulator (SOI) platform.…”

Toward High‐Speed and Energy‐Efficient Computing: A WDM‐Based Scalable On‐Chip Silicon Integrated Optical Comparator

“…Direct‐logic‐based optical comparators have also been reported in literature, which use add‐drop microresonator modulators as EO logic gates. [ 25,35 ] However, only designs of single‐bit comparators are presented, and their schemes cannot be extended to design comparators with higher bits, such as 64 or 128 bits, which are required in current computing and communication applications. A simple example is the IPV6 (Internet Protocol version 6).…”