Q. Multimode for transmitting optical signals?

- Multiple beams from light source travel through core at different paths

- Multimode step-index fiber

• Density remains constant from centre to edges
• Light moves in a straight line until it reaches the cladding
• A few beams penetrate the cladding and are lost while others are reflected down the channel to the destination

- Consequently beams reach the destination at different times and the signal mayn't be the same as that which was transmitted

- To address this problem and to permit for more precise transmissions, multimode graded-index fiber may be used

- Index demotes to the index of refraction

- Graded-index demotes to varying densities of the fiber highest at centre and decreases at edge