Section-A
INTRODUCTION TO OPTICAL COMMUNICATION SYSTEMS : Electromagnetic spectrum
used for optical communication, block diagram of optical communication system. Basics of
transmission of light rays. Advantages of optical fiber communication.
Section-B
OPTICAL FIBERS: Optical fibers structures and their types, fiber characteristics : attenuation,
scattering, absorption, fiber bend loss, dispersion; fiber couplers and connectors.
Section-C
LED LIGHT SOURCE : Light emitting diode : recombination processes, the spectrum of
recombination radiation, LED characteristics, internal quantum efficiency, external quantum
efficiency, LED structure, lens coupling to fiber, behavior at high frequencies.
LASER LIGHT SOURCE : Basic principles of laser action in semi -conductors, optical gain, lasing
threshold, laser structures and characteristics, laser to fiber coupling, comparison with LED
source.
Section-D
AVALANCHE AND PIN PHOTODETECTORS: Principles of optical detection, quantum
efficiency, responsivity, general principles of PIN photodetector, intrinsic absorption, materials and
designs for PIN photodiodes, impulse and frequency response of PIN photodiodes, noise in PIN
Photodiodes, multiplication process, APD Design, APD bandwidth, APD noise.