Applications of optical communication

Disadvantages:-

Optical Communication System Microwave System

1. Expensive transmitter and

receiver.

1. Simple and less expensive transmitter

and receiver.

2. Difficult coupling. 2. Easy coupling.

3. Power transmission depends upon

the quantum efficiency of light source

(LED or

LASER).

3. Output power is directly coupled to

the transmission line.

APPLICATIONS OF OPTICAL FIBER COMMUNICATIONS:-

1) Long distance tele communications:-

Long distance telephone carriers use optical fibers to carry the plain old

telephone service (POTS) across their high speed “backbone” systems

That carry thousands of voice signals between regions of country. The

telephone industries first widespread use of fiber optics was between the

central offices which are several kms apart and even, these are connected

by fiber cables operating at 800-900nm.

2) Medical Applications:-

The first commercial applications for fiber optics were medical. Bunaled

fibers can deliver illumination light to remote regions of the body, and

carry coherent (understandable) images back to the doctor. As a

replacement for rigid endo-scope, this became an in-valuable tool. In

recent years, they are also used to find the heart beat level, blood

pressure, sugar level etc.

3) Computer Data Communications:-

Optical fiber communications also used for transmitting digital data

generated by computers between CPU and peripherals, between CPU and

memory and between CPUs.

4) Video Transmission:-

Video signals transmission requires more bandwidth compared to audio

signals. Since the cable TV subscribers, receives the same video signal

that spreads from some common point, hence it requires more bandwidth

to provide better quality video signal to the subscriber. Fiber cables

which provides enormous bandwidth makes it the perfect choice for

transmitting broadband signals, such as high-definition television

(HDTV) 

5) Military Systems:-

Optical fibers are insensitive to Electro-Magnetic Interference and Radio￾frequency Interference (EMI/RFI). Because of this, and some recent

developments in the manufacture of radiation resistant fiber, fiber optics

are highly suitable for many military and communication applications

where high signal quality, secure data transmission, and survivability are

essential.

6) Intelligent Systems:-

Intelligent transport systems, such as smart highways with intelligent

traffic lights, automated toll booths also use optical fibers based

telemetry systems.

 INTRODUCTION TO OPTICAL FIBER WAVEGUIDES:-

 In 1910, Hondros and Debye conducted a theoretical study of transmission

of light via dielectric waveguide. In 1920, experimental work was reported by

Schriever. Cladding structure of the rod was proposed in 1950. Typical

cladded fiber optical structure is as shown in figure.

Optical fiber consists of essentially two regions.

1) The central region-core

2) The middle region-cladding

The refractive index of cladding is always lower than that of the core.

Thus cladding keeps the light waves with in the core. The cladding also

provides some strength to the core.

Optical fibers are fabricated from glass or plastic which transparent to

optical frequencies. With these materials three major types of fibers are made.