Embed Size (px)
Citation preview
Optical Fiber Communications:
Optical Network
Prof. Dr. Monir Hossen
Dept. of ECE, KUET
Dept. of ECE, Khulna University of Engineering & Technology (KUET), Bangladesh
02Dept. of ECE, Khulna University of Engineering & Technology (KUET), Bangladesh
❖ Internet Reality
❖ Optical Fiber Network Evolution
❖ Network Terminology
❖ Optical Layer
❖ Network Topologies
❖ Synchronous Optical Network (SONET)
❖ Basic Design of WDM
❖ Wavelength Options in WDM
❖ Properties of PON System
Inside
Dept. of ECE, Khulna University of Engineering & Technology (KUET), Bangladesh 03
Feb. 5, 2002
SONET
Data
CenterSONET
SONET
SONET
DWD
M DWD
M
AccessLong HaulAccess MetroMetro
Internet Reality
Optical Fiber Network Evolution
Dept. of ECE, Khulna University of Engineering & Technology (KUET), Bangladesh 04
Dept. of ECE, Khulna University of Engineering & Technology (KUET), Bangladesh 5
Network Terminology
Optical Layer
Dept. of ECE, Khulna University of Engineering & Technology (KUET), Bangladesh 6
Network Topologies
Dept. of ECE, Khulna University of Engineering & Technology (KUET), Bangladesh 7
Synchronous Optical Network (SONET)
Dept. of ECE, Khulna University of Engineering & Technology (KUET), Bangladesh 8
SONET Add Drop Multiplexers
Dept. of ECE, Khulna University of Engineering & Technology (KUET), Bangladesh 9
Generic SONET Structure
Dept. of ECE, Khulna University of Engineering & Technology (KUET), Bangladesh 10
Levels and Bit Rate for SDN and SONET
Dept. of ECE, Khulna University of Engineering & Technology (KUET), Bangladesh 11
• OC-1 is the base signal with bite rate of 51.840 Mbps
Dept. of ECE, Khulna University of Engineering & Technology (KUET), Bangladesh 12
Basic Design of WDM
Various types of WDM upon wavelength spacing– CWDM (Coarse WDM)
• Bidirectional• Triple play (1310, 1490, 1550 nm)
– DWDM (Dense WDM)
CWDM– Over than 20 nm spacing between adjacent
channels– No tight control of wavelength needed → no temp.
control– Less channel crosstalk – Known as 40% cheaper than DWDM – Limited number of wavelengths available– 18 CWDM channels can be obtained over
1271~1611 nm
Wavelength Options in WDM
Dept. of ECE, Khulna University of Engineering & Technology (KUET), Bangladesh 13
ITU G.694.2 - Nominal central wavelengths of CWDM
– 1270 1290 1310 1330 1350 1370 1390 1410 1430 1450 1470 1490 1510 1530 1550 1570 1590 1610
Why Wavelengths Spacing of 20nm?
– Uncooled lasers: wavelength change with temperature.
– Wide pass band filters : wavelength variation of ± 6-7 nm with current filter technologies.
– 1/3 of the channel spacing is needed for the guard-band.
DWDM
– Less spacing than CWDM, but, usually less than 3.2 nm spacing (3.2, 1.6, 0.8, 0.4 nm)
– Tight control of wavelength needed → DWDM LD
– Careful about the channel crosstalk → DWDM Filter
– Can provides a lot of wavelengths
Wavelength Options in WDM
Dept. of ECE, Khulna University of Engineering & Technology (KUET), Bangladesh 14
Point to Point
N fibers, 2N optical transceivers
High Bandwidth
High Fiber Plant cost because of PTP configuration of fiber pairs.
Active Star (Curve Switched)
1 fiber, 2N+2 optical transceivers
Minimum fiber/space in CO
Electrical power in the filed
High Operations & maintenance cost
PON (Passive Optical Network)
1 fiber, N+1 optical transceivers
Minimum fiber/space in CO/OLT (Optical Line Terminal)
No electrical power in the field
Low Operations cost
Properties of PON System
Dept. of ECE, Khulna University of Engineering & Technology (KUET), Bangladesh 15
PON
No Power between CO & ONU (Optical Network Unit)
No active processing (routing, switching)
Only signal power split
Tree Topology
Downstream: Broadcasting and Selection
Upstream: Multiplexing
TDM-PONEPON, BPON, GPON
Requires Control Protocol for Upstream
Requires Encryption for Downstream
WDM-PONDWDM-PON, CWDM-PON
Properties of PON System
Dept. of ECE, Khulna University of Engineering & Technology (KUET), Bangladesh 16
Thanks for Your Kind
Attention
Dept. of ECE, Khulna University of Engineering & Technology (KUET), Bangladesh 17
