OE-CAM: A Hybrid Opto-Electronic Content Addressable Memory

TL;DR

This paper introduces a novel opto-electronic content addressable memory (OE-CAM) using silicon photonics, achieving significantly faster search speeds and lower power consumption than existing CAM technologies, suitable for advanced computing applications.

Contribution

The paper presents the first experimental demonstration of an integrated silicon photonic OE-CAM with high parallelism and ultra-fast operation, surpassing traditional CAM performance.

Findings

OE-CAM operates at 25 Gbit/s with maintained bit integrity.

Achieves two orders of magnitude faster searches than other CAMs.

Reduces power-delay-product by five orders of magnitude.

Abstract

A content addressable memory (CAM) is a type of memory that implements a parallel search engine at its core. A CAM takes as an input a value and outputs the address where this value is stored in case of a match. CAMs are used in a wide range of applications including networking, cashing, neuromorphic associative memories, multimedia, and data analytics. Here, we introduce a novel opto-electronic CAM (OE-CAM) utilizing the integrated silicon photonic platform. In our approach, we explore the performance of an experimental OE-CAM and verify the efficiency of the device at 25Gbit/s while maintaining the bit integrity under noise conditions. We show that OE-CAM enables a) two orders of magnitude faster search functionality resulting in b) a five orders of magnitude lower power-delay-product compared to CAMs implementations based on other emerging technologies. This remarkable performance potential is achieved by utilizing i) a high parallelism of wavelength-division-multiplexing in the optical domain, combined with ii) 10s of GHz-fast opto-electronic components, packaged in iii) integrated photonics for 10-100s ps-short communication delays. We further verify the upper optical input power limit of this OE-CAM to be given by parasitic nonlinearities inside the silicon waveguides, and the minimal detectable optical power at the back-end photoreceivers responsivity given channel noise. Such energy-efficient and short-delay OE-CAMs could become a key component of functional photonic-augmented ASICS, co-processors, or smart sensors.