The Versatile Link project includes a work package for the assessment of suitable back end components (devices that do not reside within the harsh magnetic and radiation environments of the detectors). These components, wherever possible, should be selected from devices that are commercially available to take advantage of the developments led primarily by customers in the data and telecommunications markets. In addition to single channel devices (in the SFP+ standard), parallel optics modules are being evaluated to take advantage of the density and ease of handling of multi-channel devices. By using parallel modules and ribbon fibers, improvements in the board area needed for supporting modules and cable management can be gained.
One mature parallel standard is the SNAP12 standard with separate transmitter and receiver modules (12 channels each). This scheme nominally calls for operation at 2.7 Gbps but modules were procured and tested at 5 Gbps (to comply with the nominal Versatile Link rate). Data has been collected to characterize the performance of both the transmitter and receiver modules for this standard. The data collected will be compared to the data from SFP+ single channel devices selected as reference components for multimode versions of the Versatile Link.
The SNAP12 standard, while mature, has some disadvantages in the manner in which devices are packaged and attached to the carrier boards. Driven by emerging 100 Gbps standards in the telecommunications industry, dense parallel optical engines are becoming part of vendor portfolios. As the standards have not yet converged, there are multiple options being offered by different vendors. One option has already been evaluated and the promising results of those tests have led to an initiative to continue the evaluation of other modules from multiple vendors. Work has begun with additional vendors to design evaluation platforms for the characterization of these additional components.
As part of the Versatile Link project, limited versions of optical component samples and evaluation platforms are being made available to other members of the collaboration as well as interested customers of the Versatile Link. Since parallel optical engines are an integral part of the boards on which they are mounted, an effort is underway to design demonstrator boards of optical engines. These boards will make use of the CAPTAN data acquisition system developed by our team (Ref 1) and come in two versions, each of which can operate stand-alone or as a mezzanine card on a uTCA carrier board. One version will utilize gigabit transceivers available in FPGAs while the other version will utilize discrete commercially available SerDes devices to attain the highest bit rates at reasonable costs.
 CAPTAN: A Hardware Architecture for Integrated Data Acquisition, Control, and Analysis for Detector Development, N70-3, IEEE Nuclear Science Symposium, 2008.