Design of a multigigabit optical network interface card

High-speed optical data links enable local area networks (LANs) that operate at data rates above 10 Gb/s. Various network, protocol and switch architectures have been proposed that use these links. The optical network interface card (ONIC) is an important component for demonstrating efficient application of these architectures. In this paper, we describe the design of a programmable ONIC that interfaces a 12-channel gigabit parallel optical link module with a 64-bit/66-MHz PCI computer bus. Hardware programmability (using FPGAs) enables the ONIC to efficiently implement different communication protocols. For hardware testing, the ONIC hardware was programmed for bit error rate (BER) analysis. In continuous operation at 8 Gb/s for 30 days through a 1-m fiber, no errors occured. For application testing, a custom ONIC software driver was developed. We used this driver to demonstrate message passing between applications running on two ONIC-equipped servers. The ONIC design provides a low-cost solution that can be readily adapted for application and device specific requirements. The use of ONIC in a free-space optical switch system is described here.