Jawaharlal Nehru Technological University Hyderabad 2010-2nd Sem M.E Computer and Communication Engineering Code No: B3604 M.Tech II Sester Regular s tember OPTICAL COMMUNICATION

Code No: B3604
JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD
M.Tech II Semester Regular exams September 2010
OPTICAL COMMUNICATION & NETWORKS
(COMPUTERS & COMMUNICATION ENGINEERING)
Time: 3hours Max.Marks:60
ans any 5 ques.
All ques. carry equal marks
- - -
1. a). Based on the attenuation spectrum of silica core of an optical fiber,
explain the application of optical fiber in telecommunications.
b). Draw the block diagram of an optical link, define the functioning of
every block. Substantiate the need of every block in it.

2. a). describe Numerical aperture. Derive an expression for numerical aperture
of a Step-Index Multimode fiber.
b). elaborate lineary polarized modes that are supported by an optical fiber?
discuss the existence of these modes with the help of necessary equations
and diagrams.

3. a). discuss the operation of an Injection Laser diode through a diagram of its
hetero junction structure.
b). Establish the threshold condition for a Fabry-perot cavity laser diode for
lasing to take place.

4. a). describe 'Responsivity' and 'Quantum Efficiency' of a PIN Diode and
establish a relation ranging from them.
b). Compare and Contrast 'PIN Diode' and an 'APD' in every aspect.

5. a). Bring out the advantages and disadvantages of loose-tube buffered fiber
optic cable. Which kind of cables are used for under ground installations?
b). define the steps involved in drawing an optical fiber from its preform.

6. With necessary schematics discuss the functioning of an eight Mbps and a
2.5 Gbps fiber optic link. Why are the 2 links provided above different?
Substantiate the need for individual option of components for these two
datarates.

7. discuss briefly the functioning of the subsequent fiber optic components
with suitable diagrams:
a). Switches and Isolators
b). Couplers and splices

8. a). define the frame format of SONET. elaborate the similarities and
differences ranging from SONET and SDH?
b). what are the concept of Optical CDMA.

Earning:   Approval pending.