You can use the one which goes till 40Km 1000BASE-BX40-D and 1000BASE-BX40-U for Single-Fiber Bidirectional Applications The Cisco GLC-BX40-D-I, GLC-BX40-DA-I, and GLC-BX40-U-I SFPs operate on a single strand of standard SMF. A GLC-BX40-D-I or GLC-B...

SFP made for MM fiber is not going tp work over SM fiber. 

Too much loss in 2Km of fiber. First check fiber if you have more than a pair in the same cable then try other fibers. If fiber is fine then check SFP.

Hi Sachin,Please check the link below and had the solution. As per them you need to set Baud Rate to 1200. https://supportforums.cisco.com/discussion/11593861/cisco-2600-router-confreg-1242