If you already own cisco EWDM, then check with vendor of 16Gbps SAN that can they provide 16Gbps Optical Transreceiver (SFP) for wavelengths supported by EWDM. As cisco only providing 10G SFP. For optical system it doesnot matter whether it is 1/10/16/40 higher rates can go lesser distance without amplification. Only thing need to check whether the distance you have between EWDM system will be able to support that distance at 16Gbps rate or you need optical amplifier etc. You need to see your power budget.
If you don't have Cisco EWDM then check with SAN 16Gbps vendor what they suggest. As you have many variables to see which will be difficult for you to manage if you are new to DWDM.
