Extending a DWDM Optical Network Test System to 12 Gbps x4 Channels

A “Development Platform” for prototyping new multi-GHz ATE has recently been introduced (Keezer et al. 2009 ). The first application was a multi-channel test system for characterizing an optical network switch operating at 2.5 Gbps per channel (Keezer et al. 2009 , 2010 ). Nine transmitter channels (TX) and nine receivers (RX) were used to test the Dense Wavelength Division Multiplexing (DWDM) switching network. This present paper incorporates elements from the prototype designs into full-feature test modules targeting applications between 2.5 Gbps and 24.0 Gbps per channel. Specifically, the optical test system is extended for burst-mode 12 Gbps DWDM packets (more than 4-times the rate of the original system). Using 8 TX channels, an aggregate data rate of 96 Gbps is achieved. Alternatively, some modules can be configured to double the channel-count (up to 18) while operating at the lower 2.5 Gbps rate (45 Gbps aggregate rate). Lower rates permit use of lower-cost optical components. Two new modules are described with testability features such as: (1) support for “loopback” testing of DUT output-to-inputs, (2) DC electrical tests, (3) 2-to-1 multiplexing up to 24 Gbps, (4) ATE self-test/calibration loopback paths. Recently multiple Development Platforms have been constructed that can operate either independently or synchronized using very low-jitter (~1 ps RMS) clock distribution paths.