how can i connect
three 2960 switches with a 3560 switch using fiber opitc for distances greater than 100m.
I need uplinks of 1 Gbps from each 2960 to 3560 switch.
Check out this link
It provides information on the type of SFP you need to purchase for the 3560 and 2960s and the type of cable.
Based on your requirement, you can go with 1000BASE-SX MMF Fiber Cable.