Mumbai University > Electronics and telecommunication > Sem 7 > optical communication and networks

Marks: 05

Years: MAY 2014

• Most optical amplifiers amplify incident light through stimulated emission, the same mechanism that is used by lasers. Indeed, an optical amplifier is nothing but a laser without feedback.

• Optical amplifiers are used extensively in fiber optic data links. The above figure shows three ways in which optical amplifiers can be used to enhance the performance of optical data links.

• A booster amplifier or post-amplifieris used to increase the optical output of an optical transmitter just before the signal enters an optical fiber.

• The optical signal is attenuated as it travels in the optical fiber. An inline amplifieris used to restore (regenerate) the optical signal to its original power level. They are used in increasing transmission distance.

• An optical pre-amplifieris used at the end of the optical fiber link in order to increase the sensitivity of an optical receiver.