You can distiguish between guided and unguided media and tell about the advantages and disadvantages for the same and paste some pictures...... You can add few points like the following:
1. Optical signals pass through a solid medium means it uses wires.
2. The signals is guided by the size, shape and length of the wire.
3. E.g.- Copper Un-shielded Twisted Pair, etc.
1. Optical signals doesn't pass through a solid medium means it is wireless.
2. Frequency spectrum use the electromagnetic signals.
3. E.g.- LAN, WAN, MAN, PAN, etc.