Consider an optical fiber as a "multi-lane" public road. The traditional TDM system only uses one lane of this road. Increasing the bit rate is equivalent to speeding up the driving on this lane to…

Consider an optical fiber as a "multi-lane" public road. The traditional TDM system only uses one lane of this road. Increasing the bit rate is equivalent to speeding up the driving on this lane to increase the transportation volume per unit time. Using DWDM technology is similar to using the unused lanes on the public road to obtain the huge untapped transmission capacity in the optical fiber.