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I am interested in optical FPGAs.
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Good luck with that, they don't yet exist :)
FPGAs can be used to implement optical interfaces. The most common technique is that you route the CML-logic transceiver lanes to SFP+ (small form-factor pluggable) or QSFP+ (quad version) connectors, and then plug in either direct attach copper cables for short runs (<5m) or optical cables for longer runs (10m to many km).
Altera has some public-relations photos of an FPGA with Avago optical modules mounted on the corner of the FPGA. This is not yet a real product though (as far as I have seen).
The FPGAs you are interested in are the devices with transceiver lanes. For testing you ideally want devices with an embedded eye-pattern monitor, i.e., the Arria V GZ devices or the Stratix V series devices.
What are you interested in testing?
Cheers,
Dave