Difference between using optical amplifier and EDFA

Hi Fayiqa,

The optical amplifier component acts as a black box optical amplifier in OptiSystem, meaning it can be any type of optical amplifier. You would just need to define the characteristics such as gain and noise figure. You wouldn’t have to design its parameters in the way you have to do for EDFA.

Regards

hi alistu

how to use EDFA in multimode fiber( with proper pumping) , can you send me demo file( because there is no demo file in optisystem 14)?
and what is the differnce between MM fiber EDFA and simple EDFA ?

regards

Hello fayiqa,

As far as i know, optical amplifiers give you a better output than using EDFA particularly in optisystem. I don’t know about the theoretical aspects but that is what i have come across. And as far as processing is concerned i guess both does processing in optical domain because we are dealing with optical communication unless and until your system design is for All Optical network.

regards

hi all,

i appreciate alistu answer on this.

yes it is also true that optical amplifier (black box) provides the better results as compared to EDFA for simple optical designs in opotisystem.

but for practical purposes , there nothing like optical amplifier(black box, we have EDFA, raman amplifiers, HYbrid amplifiers.
thus in actual practical application we must use the amplifier that can be used in field.

with regards

Hello everyone,
I meant if you were talking about all optical networks then there is a huge difference between amplifiers used in those networks and the conventional optical networks. And if so then there is a difference in processing too. Well let me put it this way, In conventional optical networks, the input to the amplifier is no doubt optical but it is converted back to electrical signal and the processing (i.e amplification) inside is electrical and then signal is converted back to optical and we have optical signal at the output of amplifier. But in case of All optical network , the signal at the input of amplifier is optical, processing is in optical domain too and the signal at output is optical that means no conversion and that’s why All optical networks have less loss and less attenuation. Hope you understood.

Regards

hi aabid,

i got you point.

but mostly the amplifiers which we use in channel , commercially are all-optical.there is no conversion of optical to electrical and then back to optical form.
EDFA: uses erbium doped fiber,
raman amplier: uses non liner effects,
hybrid uses combination of both of them.

however there are amplifiers like SOA which is not all -optical.

with regards

you are welcome fayiqa

Hi all..
I ‘ll go with Aabid’s point where in he has mentioned the difference in processing.

Had the O.A and EDFA been same, the performance should have been exactly same if both were set to same values of gain.
I think so make the performance same at same values of gain, the EDFA length has to be taken in consideration.

Regards.

Hello naazira,
You got exactly what i was trying to convey. It has to do with processing. I agree with you had the amplifiers been same , then the performance should have been same but it is contrary. And as you mentioned , to make the performance same we should take length of EDFA into consideration i would like to tell you that increasing length of amplifier does not always have positive effects on our system. It can prove to be an adverse situation in some cases sometime. So we should try not to increase the length beyond optimum.
Regards

Hi Aabid..
Yes, you are right.The EDFA length can’t be increased beyong optimum. Because for a particular pump power, its gain increases upto a certain length and beyond that it decreases actually. This happens because the pump power isn’t enough to excite the doped ions of the entire length. Hence the unexcited region of the length absorbs certain part of the signal energy. Hence loss could be observed.

This has been nicely explained by Keiser. Here’s link to the page:

https://books.google.co.in/books?id=5JeN4QhYo8kC&pg=PA405&lpg=PA405&dq=after+a+certain+length,+the+EDFA+gain+decreases&source=bl&ots=Z_X1pUr48q&sig=biJNG7x1rHKLTnEJDJw4ooFRswE&hl=en&sa=X&ved=0ahUKEwj85qzr5qHLAhVMkI4KHdUqB6MQ6AEIOjAF#v=onepage&q=after%20a%20certain%20length%2C%20the%20EDFA%20gain%20decreases&f=false

Cheers. (y)

Regards.

Hello naazira,
Yeah exactly for a particular pump power, its gain increases up to a certain length and beyond that it decreases. The reason being same as you mentioned above.
Anyways thanks.
With Regards

Hi Fayiqa mam,

I think the main difference between them is that SOA has higher noise, lower gain, moderate polarization dependence and high nonlinearity with fast transient time, But SOA requires less power than EDFA.

Hi all..
I would like to ask if these O.A could be used in systems other than the All -Optical Networks?

Regards.

Hi All..
All the replies above are valid.(y)

I have made use of an ‘Optical Amplifier’in my FSO system. In Optiwave, in the Optical Amplifiers library,there are amplifiers with names EDFA, SOA and OA . I have made use of an OA. I believe it is this one when you mention the usage in all-optical networks, right?

Regards.

hi naazira,
EDFA, SOA and OA,
EDFA and SOA have there usual meaning which we all know(ie. erbium doped fiber amplifier and semiconductor optical amplifier,)

there amplifier have both simulation and practical importance.

where OA refers to optical amplifier , and acts as black box which has function of amplifiyiny optical pulse.

these have only simulation importance, however for practiacl application we can design amplifier of same characteristics as that of OA.

with regards

Hi Aasif..
Thanks for the reply.
Well yeah.. in that case we can rely on the results based on employment of OA in our system because these characteristics could be achieved in amplifiers like EDFA.

Regards.

okay Aabid.
Thanks for sharing.

Regards.

you are welcome naazira.
It was a nice discussion.
Best Regards

Hello everyone,
I meant if you were talking about all optical networks then there is a huge difference between amplifiers used in those networks and the conventional optical networks. And if so then there is a difference in processing too. Well let me put it this way, In conventional optical networks, the input to the amplifier is no doubt optical but it is converted back to electrical signal and the processing (i.e amplification) inside is electrical and then signal is converted back to optical and we have optical signal at the output of amplifier. But in case of All optical network , the signal at the input of amplifier is optical, processing is in optical domain too and the signal at output is optical that means no conversion and that’s why All optical networks have less loss and less attenuation. Hope you understood.

Regards

Hi Fayoqa,
i want to discuss the characteristics and disadvantages of different optical amplifiers which will help you to solve your problems.
Advantages & Disadvantages of EDFA
Advantages
Wide spectral band amplification with relative flat gain (>20 dB) – useful for
WDM applications.
Saturation output > 1 mW (10 to 25 dBm).
Gain-time constant long (>100 msec) to overcome patterning effects and intermodulation
distortions ( low noise).
Large dynamic range.
Low noise figure.
Polarization independent.
Suitable for long-haul applications.
This EDFA has high pump power utilization (>50%)
Directly and simultaneously amplify a wide wavelength band (>80nm) in the 1550nm region, with a relatively flat gain
Flatness can be improved by gain-flattening optical filters
Gain in excess of 50 dB
Low noise figure suitable for long haul applications
Disadvantages

Size of EDFA is not small
It can not be integrated with other semiconductor deviecs
Thanks,

Hi,
This is the Characteristics of SOA types:
Polarization dependent – require polarization maintaining fiber
Relatively high gain ~20 dB
Output saturation power 5-10 dBm
Large BW
Can operate at 800, 1300, and 1500 nm wavelength regions.
Compact and easily integrated with other devices
Can be integrated into arrays
High noise figure and cross-talk levels due to nonlinear phenomenon such as 4-
wave mixing.
The semiconductor optical amplifier is of small size and electrically pumped.
It can be potentially less expensive than the EDFA and can be integrated with semiconductor lasers, modulators, etc.
All four types of nonlinear operations (cross gain modulation, cross phase modulation, wavelength conversion and four wave mixing) can beconducted.

Disadvantages
The performance of SOA is still not comparable with the EDFA. The SOA has higher noise, lower gain, moderate polarization dependence and high nonlinearity with fast transient time.

Thanks,
In this way both are different from each other.

Hi,
Fiber amplifiers used in WDM systems usually make use of control systems as power or gain. Designs Er-doped fiber amplifiers by considering numerical solutions of the rate and the propagation equations under stationary conditions. The model includes amplified spontaneous emission (ASE) as observed in the amplifier Erbium Doped Fiber.
The main difference is related to the amplifier pump scheme selection. You can choose co-propagating, counter-propagating, or bi-directional pump schemes with the option to set wavelength and pump power. Geometrical Er-doped fiber parameters and cross-section curves are required as input files. As output files, you can access gain, output power values, and noise figure determined in the ASE bandwidth set as noise input data.
Enables the design of amplifiers, including EDFAs, that consider pre-defined operational conditions. This means that expected gain, noise figure, and amplifier output power can be previously specified. The amplifier presents the same facilities as a black box model, which enables you to select the operation mode with gain control, power control, or to perform simulations under saturated conditions, as well as define the expected amplifier performance. It is specially suited to perform prompt performance analysis of one or cascaded amplifiers in a long-haul system.

Hope this helps.
Thanks

I also want to bring to your notice that In optical fiber library we have different types of amplifier lke Raman amplifier, EDFA amplifier and Semiconductor optical amplifier(SOA).I want to share characteristics of different amplifiers, now the selection of different amplifiers depends upon its application, feasibilty, power pumping availability we have.
Characteristics of SOA types:
Polarization dependent – require polarization maintaining fiber, Relatively high gain ~20 dB , Output saturation power 5-10 dBm, Large BW
Can operate at 800, 1300, and 1500 nm wavelength regions., Compact and easily integrated with other devices, Can be integrated into arrays , High noise figure and cross-talk levels due to nonlinear phenomenon such as 4-, wave mixing. This last feature restricts the use of SOAs. Limited in operation below 10 Gb/s. (Higher rates are possible with lower gain.
Thanks