Technical ADTRAN does not support any modules outside of our compatible SFP list. However, many other modules will work assuming they use relatively the same tolerances and support the same speeds. In many cases, other vendors SFP modules do work, but in some cases they do not as well.
The only SFP products we make that have a narrow support range are the SFP+ XIM modules for the 1638. These only support ADTRAN SFP+ modules. Non-ADTRAN modules will not function in these XIMs.
Please feel free to let me know if you have more questions.