Tip of the Week – 12 Jan 2011

Tip of the Week:
Fiber network capacity can be expanded economically using simple CWDM or DWDM multiplexers and proper transceivers.  But which is better, CWDM or DWDM technology?  It depends on your present and future channel requirements, fiber type, fiber link length and budget. Here is a list of advantages and disadvantages for both technologies.
CWDM – Advantages
a. Lower equipment costs compare to equivalent DWDM system. b. Great for metro application with low channel count. c. Simple optical add/drop multiplexers (OADM) available for mid span access. d. Can be used in 1 or 2 fiber spans.
CWDM – Disadvantages
a. Restricted to maximum 18 channels and possibly 8 channels max with older fiber types that have high channel loss below channel 1471nm. b. EDFA optical amplifiers are not available for CWDM systems, however SOA and EDFA optical amplifiers can be used to amplify individual channels in some cases. c. Difficult and costly to extend transmission distance past transceiver’s optical budget or chromatic dispersion limit. d. Difficult to source 10Gbps transceivers. Most CWDM transceivers are available for transmission rates of 100 mbps to 2.5 Gbps.
DWDM – Advantages
a. More capacity, multiplexers and transceivers are available from 2 to 160 channels. b. Transceivers available for all transmission rates, 1Gbps, 2.5Gbps, 10Gbps, 40Gbps.
c. Transmission distance can be extended with optical amplifiers and dispersion compensation.
d.  Simple and elaborate optical add/drop multiplexers (OADM & ROADM) available for mid span access
e.  More flexibility, can be used in metro and/or long haul applications.
f.   Can be used in 1 or 2 fiber spans.
DWDM – Disadvantages
a. Higher equipment costs compared to equivalent CWDM system. b. Pertinent Products/Services Pertinent products and services:
Need help installing, provisioning, testing, debugging and maintaining your fiber network? Give us a call.  We can provide you will these services during normal business hours or as 24×7 emergency support.
 Some of our expertise includes:
  • DWDM and CWDM systems
  • local, metro and long haul systems
  • optical amplifier systems (EDFA, SOA, Raman)
  • SONET and Ethernet over fiber
  • 48vdc power
  • BER and Ethernet RFC2544 testing
  • fiber characterization
  • network debugging
Need to expand your fiber network with CWDM or DWDM multiplexers, ROADMs and/or transceivers? Gives us a call or visit our product page at  www.TelecomEngineering.com/products.htm for our latest in fiber transmission technologies.
Contact us toll free 1-888-250-1562 or email at t info@TelecomEngineering.com for more details and pricing.
To learn more about this topic and other fiber optic network topics, refer to my following books (publisher McGraw-Hill):
“Planning Fiber Optic Networks”, ISBN 0-07-1499199 available from Amazon.com .  Table of contents can be seen here :  http://www.TelecomEngineering.com/products/resources/planningfibernetworks.htm ,
“Fiber Optic Installer’s Field Manual”, ISBN 0-07-135604-5 available from Amazon.com. Table of contents can be seen here http://www.TelecomEngineering.com/products/resources/field-manual.htm .
Did you miss last week’s Tip?  If so feel free to peruse this month’s archived Tips at https://www.telecomengineering.com/About_us/Tip_of_week/tipofweek.htm
For information about our products and pricing contact us at toll free 1-888-250-1562 .
If you have any questions regarding this tip or other fiber networking concerns, please feel free to email me at BChomycz@TelecomEngineering.com.
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*Note: All prices shown are in US$ and products are shipped FOB Minnesota, USA. Prices may change without notice.
Bob Chomycz, P.Eng.
Telecom Engineering, Inc. Telecom Engineering USA, Inc. Toll Free:  1.888.250.1562 www.TelecomEngineering.com