Co-development of test electronics and PCI Express interface for a multi-Gbps optical switching network

This paper presents the design and performance characteristics of a system designed to interface between a PCI Express port and an optical packet switched network as well as provide inline test capability for the whole system. A single lane of PCI Express traffic is inverse multiplexed across eight parallel channels and retransmitted in a burst packet at aggregate data rates of 20 to 36 Gbps. Testing options include loopback self-test, data synthesis and substitution in-line with or in place of system data, and variable channel-to-channel skew. The I/O interfaces also support a range of variable analog parameters such as peak output amplitude, output amplitude swing, and common mode ranges for the input and output to evaluate the performance of or adapt to changes in the opto-electronic components. This design flexibility also allows for use of the system in more conventional electronic applications with little or no required modifications.