All-Optical Content-Addressable Memory (CAM) Based on All-Fiber Platform

Abstract

The advent of optical CAM (O-CAM) is promising in addressing challenges related to data traffic growth and ultrafast signal processing in modern optical communication systems. O-CAM, based on semiconductor optical amplifiers (SOA) and silicon microring resonators, can achieve fast CAM. However, these devices have limitations, such as high cost, complex systems, and the need for high precision manufacturing technology. Herein, we propose an all-optical CAM based on fiber and Ge₂Sb₂Te₅ (GST). The device structure is simple and easy to manufacture, and it does not require additional photoelectric conversion or coupling between the fiber and waveguide. We first use the core of side-etched seven-core fibers (SCF) to achieve 22-level storage. Next, CAM is realized by a Mach–Zehnder (MZ) interferometer composed of two fiber cores of SCF. Finally, we achieve a 3-bit CAM by using a single SCF, and we can determine the degree of matching. The maximum average energy density for an individual CAM cell is 5.72 nJ/μm² and it requires no continuous power input to maintain the switching states, which is naturally advantageous given the low power density and the long intervals between entry updates in modern optical packet switching systems.