All-optical ternary-content addressable memory (T-CAM) cell and row architectures for address lookup at 20 Gb/s

Content addressable memories form a popular design choice for routing table implementations thanks to their fast searching capabilities. However, high speed address look-up operation is still challenging due to the speed limitations imposed by conventional electronic technologies. In this paper, we demonstrate a completely optical ternary-content addressable memory (T-CAM) cell architecture that extends the capabilities of the experimentally demonstrated 10 Gbps optical binary-content addressable memory cell to the third matching state “X” or “Care/Don’t Care”, enabling in this way the subnet-masked operation that is necessary in modern router applications. Additionally, we present a 4-cell T-CAM row architecture introducing wavelength division multiplexing-enabled matchline decoding so as to allow for comparison operation with complete optical words. The performance of both the optical T-CAM cell and the optical T-CAM row architectures is evaluated by means of physical layer simulation results, presenting successful Search and Write operation at 20 Gb/s.