I have been looking for high bandwidth, high fidelity CDR modules for high speed (25Gbps and beyond) SerDes characterizations and finally it's here! It is Agilent 86108B Precision Waveform Analyzer which claimed to have "industry best intrinsic jitter below 50 femtoseconds, channel bandwiths to 50GHz, and clock recovery to 32Gbps ...."
If you are interested to know more, "Tips and Techniques for Accurate Characterization of 28Gb/s " is one of their good application notes to start with.
