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As routing tables in core Internet routers grow to exceed 100,000 entries, it is becoming essential to develop methods to reduce the lookup time required to forward packets toward their destinations. In this paper, we employ a bank of novel thermally tuned fiber-Bragg-grating-based optical correlators to construct an "optical bypass" to accelerate conventional electronic Internet routers. The correlators are configured as a routing table cache that can quickly determine the destination port for a fraction of the incoming traffic by examining only a subset of the bits in an IP packet's 32-bit destination address. We also demonstrate a novel multiwavelength correlator based on fiber Bragg grating that can simultaneously recognize the header bits on multiple wavelengths for use in wavelength-division-multiplexed (WDM) systems. Using the optical bypass, routing table lookup times are reduced by an order of magnitude from microseconds to nanoseconds and are limited only by the speed of the optical switch.
Date of Publication: Nov. 2003