1. Mohammad Sakib Ullah Summit Communications Limited NOC Date:05/03/2016
Training on DWDM
Mohammad Sakib Ullah
Summit Communications Limited
NOC
Date:05/03/2016

2. Objectives Understand how DWDM system works
Understand Optical Power Debugging in DWDM system
Understand Common Alarms of DWDM system

3. Outline DWDM system overview Optical Power Debugging
Common Alarms Analysis
Alarm Monitoring
PGCB network of SCL

4. Growing Network Usage Patterns
Issues
Exponential increase in user demand for bandwidth
Doubling of bandwidth requirement every 6-9 months
Consistency in quality of services provided
Keeping the cost of solutions at bay
Solutions
Increase channel capacity: TDM, WDM
Statistical multiplexing of users: Multiple optical fibers

5. Another glimpse at the Solutions
TDM (Time Division Multiplexing)
Slotting of channels  simultaneous users
Increasing bit rate to maximize utilization of given bandwidth
WDM (Wavelength Division Multiplexing)
Use of optical fibers to achieve higher speeds
Utilize wavelengths to multiplex users
Allow continuous channel allocation per user
Increases the effective bandwidth of existing fiber

6. Limitations of current Solutions
TDM
Dependency of Mux-Demux on bit rate
Limitations on bit rates
how fast can we go? (Decides how small the time slots can be)
WDM
Inefficient usage of full capacity of the optical fiber
Capability of carrying signals efficiently over short distances only

7. What is DWDM ?
It transmits multiple data signals using different wavelengths of light through a single fiber.
Incoming optical signals are assigned to specific frequencies within a designated frequency band.
The capacity of fiber is increased when these signals are multiplexed onto one fiber.
Transmission capabilities is 4-8 times of TDM Systems with the help of Erbium doped optical amplifier.
EDFA’s : Increase the optical signal and don’t have to regenerate signal to boost it strength.
It lengthens the distances of transmission to more than 300 km before regeneration.

8. Simple DWDM System
Multiple channels of information carried over the same fiber, each using an individual wavelength
Transmitter T1 communicates with Receiver R1 as if connected by a dedicated fiber as does T2 and R2 and so on

9. DWDM Advantages Greater fiber capacity Easier network expansion
No new fiber needed
Just add a new wavelength
Incremental cost for a new channel is low
No need to replace many components such as optical amplifiers
DWDM systems capable of longer span lengths
TDM approach using STM-64 is more costly and more susceptible to chromatic and polarization mode dispersion
Can move to STM-64 when economics improve

10. DWDM Disadvantages Not cost-effective for low channel numbers
Fixed cost of mux/demux, transponder, other system components
Introduces another element, the frequency domain, to network design and management
SONET/SDH network management systems not well equipped to handle DWDM topologies
DWDM performance monitoring and protection methodologies developing

11. Optical Power Debugging
Basic Knowledge
Optical Power Unit
mW (Milli-watt)
Commonly used optical power unit
dBm (Decibel for milli-watt)
Optical power unit for the easy calculation
dB (Decebel)
Value for the optical power increased or decreased
Relationship between mW and dBm
A (dBm) = 10lgA (mW)
B(mW)=10B/10(dBm)

12. Optical Power Debugging Purpose
We have 3 Purposes:
1. Make each channel has the same the optical power in the transmission.
2. Make the OA working in the Best State.
3. Make the OTUR working in the Best State.
OTU … O M U
OBA
OPA D
OTUR: Optical Transponder Unit Receive
OUT: Optical Transport Unit
OMU: Optical Multiplexer Unit
ODU: Optical De-multiplexer Unit

13. Basic Optical Power Balancing Calculation
P λN
Formula 1:
PN=Pλ1+Pλ2+Pλ3+…+PλN (mW)
PN=P1+P1+P1+…+P1 (mW)
Because Pλ1=Pλ2=…=PλN = P1
=N×P1 (mW)
10lgPN=10lg(N×P1)
=10lgN+10lgP1
PN=10lgN+P1
Because 10lgPN (mW) =PN (dBm)
PN=10lgN+P1 (dBm)

14. Basic Optical Power Balancing Calculation
Formula 2:
Pin
Pout O M U
Suspended
IL (Insertion Loss)
Pin
Pout O D U
IL (Insertion Loss)
Pout = Pin/IL (mw)
10lgPou t= 10lgPin-10lgIL
Because 10lgPout((mw) = Pout(dBm)
10lgPout((mw) = Pout(dBm)
Pout=Pin- IL (dBm)

15. Basic Optical Power Balancing Calculation
Formula 3:
Pin
Pout
G (Gain) OA
Pout = Pin×G (mw)
10lgPout = 10lgPin+10lgG
Because 10lgPout((mw) = Pout(dBm)
Pout=Pin+G (dBm)

16. Basic Optical Power Calculation
APD
-3dBm
ch1 λ1 λ1
ch1
OTU1
1412
OMU32
1620
OTU1
ODU32
Input ┇ BA PA ┇
Output λn λn
ch5
ch5
OTUn
OTUn
Line loss = 20dB
Insertion loss = 7dB
Insertion loss = 7dB
The Maximum Capacity of this DWDM system is 2.5G╳32Chs.
Now, there are only five channels in this system.
Question: Where and what attenuation the attenuators should be added in the system?
Re: lg32=1.5, lg5=0.7

17. Basic Optical Power Calculation (OMU)
APD
-3dBm
ch1 λ1 λ1
ch1
OTU1
OMU32
OTU1
1620
1412
ODU32
Input ┇ BA PA ┇
Output
ch5 λn λn
ch5
OTUn
OTUn
Line loss = 20dB
IL = 7dB
IL = 7dB
Pin
Pout
P1out=P1in-IL (Formula 2)
=-3-7
=-10(dBm)

18. Basic Optical Power Calculation (OBA)
APD
-3dBm
ch1 λ1 λ1
ch1
OTU1
OMU32
OTU1
1620
1412
ODU32
Input ┇
Output BA PA ┇ λn λn
ch5
ch5
OTUn
OTUn
Line loss = 20dB
IL = 7dB
IL = 7dB
Pin
Pout
P32out=P1out+10lg32 (Formula 1)
P1out=P32out-10lg32
=20-15
=5(dBm)
P1out=P1in+G (Formula 3)
P1in=P1out-G
=5-16
=-11(dBm)

19. Basic Optical Power Calculation
APD
-3dBm
ch1 λ1 λ1
ch1
OTU1
OMU32
OTU1
1620
1412
ODU32
Input ┇ BA PA ┇
Output λn λn
ch5
ch5
OTUn
OTUn
Line loss = 20dB
IL = 7dB
IL = 7dB
PoutOMU
PInOBA
Attenuation = P1outOMU-P1inOBA
= -10-(-11)
= 1(dB)
Before OBA: 1 dB attenuation

20. Basic Optical Power Calculation
APD
-3dBm
ch1 λ1 λ1
ch1
OTU1
OMU32
OTU1
1620
1412
ODU32
Input ┇
Output BA PA ┇
ch5 λn λn
ch5
OTUn
OTUn
Line loss = 20dB
IL = 7dB
IL = 7dB
PoutOBA
PAfter Line
PAfter Line = P1outOBA-Line Loss
= 5-20
= -15(dBm)

21. Basic Optical Power Calculation (OPA)
APD
-3dBm
ch1 λ1 λ1
ch1
OTU1
OMU32
OTU1
1620
1412
ODU32
Input ┇ BA PA ┇
Output λn λn
ch5
ch5
OTUn
OTUn
Line loss = 20dB
IL = 7dB
IL = 7dB
Pin
Pout
P32out=P1out+10lg32 (Formula 1)
P1out = P32out-10lg32
= 12-15
= -3(dBm)
P1out=P1in+G (Formula 3)
P1in= P1out-G =
= -17(dBm)

22. Basic Optical Power Calculation
APD
-3dBm
ch1 λ1 λ1
ch1
OTU1
OMU32
OTU1
1620
1412
ODU32
Input ┇ BA PA ┇
Output λn λn
ch5
ch5
OTUn
OTUn
Line loss = 20dB
IL = 7dB
IL = 7dB
PAfter Line
PInOPA
Attenuation = PAfter Line-P1inOPA
= -15-(-17)
= 2(dB)
Before OPA: 2 dB attenuation

23. Basic Optical Power Calculation (ODU)
APD
-3dBm
ch1 λ1 λ1
ch1
OTU1
OMU32
OTU1
1620
1412
ODU32
Input ┇ BA PA ┇
Output λn λn
ch5
ch5
OTUn
OTUn
Line loss = 20dB
IL = 7dB
IL = 7dB
Pin
Pout
P1out = P1in-IL (Formula 2)
P1in = P1out+IL =
= -7(dBm)

24. Basic Optical Power Calculation
APD
-3dBm
ch1 λ1 λ1
ch1
OTU1
OMU32
OTU1
1620
1412
ODU32
Input ┇ BA PA ┇
Output λn λn
ch5
ch5
OTUn
OTUn
Line loss = 20dB
IL = 7dB
IL = 7dB
PoutOPA
PinOMU
Attenuation = P1outOPA-P1inODU
= -3-(-7)
= 4(dB)
Before ODU: 4 dB attenuation

25. Alarm Classification Communication Alarms
Alarms that affect the service layer, indicating communication signal interruption or failure
Equipment Alarms
Equipment or cards fault alarm
Environment Alarms
Environment monitor alarms, such as fire, flood, or equipment room alarm
Maintenance Alarms
Wrong configuration or abnormal operation in EMS

26. Optical Communication Alarm
Input Power Overload Alarm
Input Power Weak Alarm
No Input Power Alarm
Output Power Too High Alarm
Output Power Too Low Alarm
No Output Power Alarm

27. Equipment Alarm AWG Temperature Over Threshold Alarm
OMU/ODU AWG module temperature over threshold.
Handling: The temperature of AWG should be around 70 ℃ for normal working, check the environment , if traffic is interrupted, replace the card.
Card Environment Temperature Alarm
The card environment is too high
Handling: Check the working status of Fan cards or the environment of equipment room.
FAN Alarm
Fan speed too low or too high.
Handling: Reset or replace the fan card.
Power Off Alarm
No power input for power card.
Handling: Check the air switch of the power distribution box, check the cable and connection.

28. Environment Alarm External fuse blowout alarm External power alarm
External power module error alarm
External AC power off alarm
External battery equally charging
External DC voltage error alarm
Solar logic alarm
Smoke
Flood
External power alarm
External flood alarm
External temperature alarm
External humidity alarm
External fire alarm
External invasion alarm
External Moving object alarm
External glass broken alarm
External lightning alarm
External battery over high voltage alarm
External battery over low voltage alarm

29. Maintenance Alarm Card Mismatched:
Card configuration in the DB is not the same as what is mounted in the physical equipment.
Handling: Remove the card and “auto find” it in the EMS.
Card Dismount:
The card is not mounted in the physical equipment.
Handling: Remove the card in the EMS or insert a corresponding card in the slot.
Card not Configure:
The card is not configured in the DB.
Handling: Remove the card from the equipment or “auto find” the card in the EMS.

30. Alarms Need to Monitor Sl. No. Display Name Original Alarm 1
Low volt battery
Battery Low Voltage 2
Fire
Fire Alarm 3
Open door
Door Open 4
Power problem
Mains Fail 5
AC power
Air-Con Fail 6
Power module problem
Rectifier Module Fail 7
Fuse
Load CB Fail 8
High Temp
Room High Temp

31. PGCB Network of SCL

32. PGCB Network of SCL

33. PGCB Network of SCL

34. PGCB Network of SCL