What is difference between Optical SFP Module and Ethernet SFP Module ?

Optical SFP Module is usually in pairs, a TX sender, a receiver of RX, MB switch port type is commonly SC card with square opening, Gigabit switches is usually SFP optical module, port type for the LC. Ethernet port also is so, refers to the so-called front-end ports gigabit switches have 10 m / 100 m / 1000 m so, generally correlates of switches is 10 m / 100 m front-end ports.