EDFA Optimizing the EDFA Gain for WDM using Optiwave Software.

1. EDFA OPTIMIZING
THE EDFA GAIN
FOR WDM
OPTICAL FIBER COMMUNICATION
PRESENTED BY:
ADITYA KHATOKAR J
(16UG09001)
DEPARTMENT OF ELECTRONICS
AND COMMUNICATION, CMRU,
SOET, BENGALURU

2. CONTENTS
DEPT. OF ECE, CMRU, SOET 2
ERBIUM DOPED
FIBERAMPLIFIER (EDFA)
EDFAPROFILEAND INSIDE
VIEW
EDFAOPERATION EDFA
WAVELENGTH OPERATION
EDFAMPLIFICATION
EDFAGAIN
FLATTENING ISSUE
EDFAOPTIMIZING THE
EDFAGAIN FOR WDM
LAYOUTAND
ITS SPECIFICATIONS
EDFAOPTIMIZING THE
EDFAGAIN FOR WDM
DESIGN SPECIFICATIONS
WORKING PRINCIPLE OF
DESIGN
SIMULATION OUTPUT

3. ERBIUM DOPED FIBER
AMPLIFIER (EDFA)
• Commercially available since the early
1990’s
• Works best in the range 1530 to 1565
nm
• Gain up to 30 dB (1000 photonsout per
photonin) Fig. 1.1 EDFA
3DEPT. OF ECE, CMRU, SOET

4. EDFA PROFILE AND INSIDE VIEW
Fig. 2.1 Profile View
Fig. 2.1 Inside View
4DEPT. OF ECE, CMRU, SOET

5. EDFA OPERATION
Higher the population inversion lower the
amplifier noise.
980 nm pump is preferred for low noise
amplification.
At 1480 nm, silica fibers have low loss and hence
pump can co-propagate with the signal
Pump may even be placed remotely Fig. 3.1 EDFAOperation
5DEPT. OF ECE, CMRU, SOET

6. EDFA WAVELENGTH
OPERATION
• Erbium‐doped fiber, however, has a
relatively long tail to the gain
shape extending well beyond this
range to about 1605 nm.
• Gain spectrum of erbium is much
flatter intrinsically in the L‐ band than
in the C‐band.
• Pump powers required for L‐band
EDFAs are much higher than their
C‐band counterparts. Fig. 4.1 Profile View
6DEPT. OF ECE, CMRU, SOET

7. EDF AMPLIFICATION
• Erbium‐doped fiber is usually
pumped by semiconductor lasers at
980 nm or 1480 nm.
• A three‐level model can be used
for 980‐nm pumps, while a two‐level
model usually suffices for 1480‐nm
pumps.
• Complete inversion can be achieved
with 980‐nm pumping but not with
1480‐nmpumping.
Fig. 5.1 EDFAmplification
7DEPT. OF ECE, CMRU, SOET

8. EDFA GAIN FLATTENING
ISSUE
• Population levels at different bands vary
and hence the gain variation. Also
affects WDM systems and to overcome
this we use filter inside amplifier and
user fluoride glass fiber.
• Difference between power of
the signals ΔP exceeds 5–10 dB and the
bit error rate is too strongly degrade.
• Filters are then introduced to selectively
add losses to high gain wavelengths
Fig. 6.1 EDFAGain
8DEPT. OF ECE, CMRU, SOET

9. EDFA OPTIMIZING THE EDFA GAIN FOR WDM LAYOUT AND ITS
SPECIFICATIONS
• Bit Rate: 2.5e+009bits/sec
• SequenceLength: 16 bits
• Samples Per Bit: 16
• Number of Samples: 256
• Symbol Rate: 40e+009 Hz
• Reference Wavelength: 1550
nm
Fig. 7.1 Layout and Specifications
9DEPT. OF ECE, CMRU, SOET

10. EDFA OPTIMIZING THE EDFA GAIN FOR WDM DESIGN
SPECIFICATIONS
1. WDM Transmitter
• Frequency:1558 nm
• FrequencySpacing: -0.8 nm
• Power: -23.5 dBm
• ModulationType: NRZ (Non-Return to
Zero)
2. Ideal Mux
• Number of Input Ports: 16
3. EDF Properties
• Length: 4.75 m
• Core Radius: 2.2 um
• Numerical Aperture:0.24
• Loss: 0.1 dB/Km
4. Pump LaserArray Properties
• Frequency:: 980 nm
• Power: 15.35mW
10DEPT. OF ECE, CMRU, SOET

11. WORKING PRINCIPLE OF DESIGN
• The gain of the EDFA will be flattened by optimizing the fiber length and pump power.
• Implementing a WDM system including EDFA’s is that the EDFA gain spectrum is wavelength
dependent is difficult. This effect results in SNR differential between channels after passing
through a cascade of EDFA’s.
• The fiber parameters in our simulation might be different than that of since no value is given.
11DEPT. OF ECE, CMRU, SOET

12. WORKING PRINCIPLE OF DESIGN
• The input of EDFA is 16 equalized wavelength multiplexed signals in the wavelength region of 12 nm
(1546-1558nm) with 0.8 nm separations.
• Power of each channel is -26 dBm and the desired gain is 23 dB.
• An outputpower of more than 8.5 dBm and a gain flatness of less than 0.5 dB.
• Fiber length and pump power is selected as parameters to be optimized to achieve the
desired gain underoutputpower and gain flatness constraints.
12DEPT. OF ECE, CMRU, SOET

13. WORKING PRINCIPLE OF DESIGN
• The Dual Port WDM Analyzer measures gain and flatness, whereas the Optical Power Meter measures the
outputpower.
• Pump power is 100 mW; fiber length is 4 m. The pump power is bound between 0 and 160 mW.
• The fiber length is bound between 1 and 40 m. Parameter termination toleranceis 1, result and constraints
termination toleranceis 0.1.
13DEPT. OF ECE, CMRU, SOET

14. SIMULATION OUTPUT
14DEPT. OF ECE, CMRU, SOET

15. DUAL PORT WDM ANALYZER
Fig. 10.1 DualPort WDM Analyzer
15DEPT. OF ECE, CMRU, SOET

16. SIGNAL AND NOISE SPECTRUM
OF AN UN-OPTIMIZED EDFA
• When pump power and fiber length are 100
mW and 4 m.
• The average gain is about 30 dB, gain
flatness is about 2.24 dB, which is much
higher than required.
• Amplitude:
Max: -2.012620688149269
Min: -104.6660656815167
Fig. 10.2 Signaland Noise of an Un-Optimized
EDFA 16DEPT. OF ECE, CMRU, SOET

17. OUTPUT SIGNAL AND
NOISE POWER SPECTRUM
• Optimum pump power and fiber length are
found to be 24.13 mW and approximately
5.22 m.
• At these values, an average gain of 23 dB
and a gain flatness of 0.29 dB are
achieved.
• The output signal power is about 8 mW.
The outputsignal and noise spectrum.
Fig. 10.4 Output Signaland Noise PowerSpectrum
17DEPT. OF ECE, CMRU, SOET

18. OPTICAL POWER METER
Fig. 10.3 OpticalPowerMeter
18DEPT. OF ECE, CMRU, SOET

19. SUMMARY
DEPT. OF ECE, CMRU, SOET 19
WDM Transmitter - wavelength division multiplexing is a technology in which
multiple optical signals of different wavelengths or colors are combined into one
signal and is transmitted over the communication channel.
Ideal Mux - the ideal mux multiplexes a user defined number of input WDM
signal channels.
EDFA - is a device that amplifies an optical fiber signal. It is used in the
telecommunications field and in various types of research fields.
Pump Laser Array – a laser used as an energy pump in an optical amplifier or
other laser by transferring or injecting energy from one wavelength to another in a
medium, often a doped fiber.
Optical Spectrum Analyzer - is a precision instrument designed to measure and
display the distribution of power of an optical source over a specified wavelength
span.
Optical Power Meter - is a device used to measure the power in an optical
signal. The term usually refers to a device for testing average power in fiber optic
systems.

20. THANK YOU...!!!