I have a WS-X6816-10G-2T module with X2-10GB-SR modules. I will be getting a SMF hand off and the length of the termination is around 100 meters. (I will be getting another hand off for Inter-DC link for which I have X2-10GB-LR module). The question is can I connect this SMF hand off (short length) on the SR module? If so what is the penalty i.e. Signal Loss etc.
Multimode equipment will not launch (inject) enough light into a single-mode fiber since the light carrying core of this fiber is only 9 microns in diameter compared to 62.5 microns in diameter for multimode fiber. It's like connecting 50 ohm coax cable to a 75 ohm coax cable. The impedence mismatch basically kills the signal and you could end up damaging equipment over time as a result.
Your only true course of action would be to get SM to MM converters and then you would be ok.