Use FWDM for Dual Fiber SFP Module
If we have only one core fiber and you have to use dual fiber sfp then we have a solution for you. You can use a FWDM or CWDM at both end . If you are using FWDM you have to use 1550nm SFP at one end and other than 1550 (e.g. 1310, 1270, 1330 etc) to another end. Note that here we are talking about double fiber sfp.