Difference between using optical amplifier and EDFA

[FAYIQA NAQSHBANDI]

I would like to know what is the main difference between using EDFA and optical amplifier when both can be used to give near about same performance?? Is there any exclusive difference between the two types of amplifiers??

[alistu]

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

[FAYIQA NAQSHBANDI]

Hello Alistu, Thank you for the reply.
But alistu if you check the properties of the optical amplifier as well as EDFA both have their properties mentioned and each of the two can have their characteristics defined by the user. I guess that is not the issue with both. I want to know if there is any difference with reference to their processing domains like EDFA processes signal in one doamin and optical amplifier in another doamin.
I would appreciate your concern

[alistu]

Hi Fayiqa,

As I have mentioned, the optical amplifiers act as a black box, which means you wouldn’t need to set the PHYSICAL characteristics of an amplifier for them. You directly set the gain, noise figure and so on from the very beginning. But in EDFA, you meed to set the physical parameters of the component so that the outcome in terms of gain and noise figure are desired for your purpose.

Regards

[prakash jat]

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

[alistu]

Hi Prakash,

I haven’t worked much with multimode optical amplifier, but what about the OptiSystem example available in OptiSystem sample files? The name of the .osd file is “Er doped multimode fiber” and it is available in the amplifiers library. I ran it and it seems that it is working properly.

Regards

[Aabid Baba]

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

[alistu]

Hi Aabid,

The reason for optical amplifiers having a better performance in your simulations (and also in mine) may be the fact that their setup is much easier than the EDFA in my opinion. Otherwise, if you set up EDFA for a gain more than that of optical amplifier and a noise figure less than that, the results would be better.

Regards

[FAYIQA NAQSHBANDI]

Hi,
Thank you for your reply aabid.

Please aabid can you explain what did you mean by saying unless and until it is all optical network??
Is it different there and if you are talking about optisystem only??
Further Replies will be appreciated. Thanking you people in advance.

[aasif bashir dar]

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

[Aabid Baba]

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

[aasif bashir dar]

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

[FAYIQA NAQSHBANDI]

Thank you everyone for your responses and i appreciate your participation.
I got what i was looking for.
Thank you Alistu for differentiating between the two amplifiers and i very well got your point. Thank you asif.
Thank you Aabid for sharing extra bit of information on amplifiers used in all optical and conventional networks.
Regards

[aasif bashir dar]

you are welcome fayiqa

[Naazira Badar]

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.

[Aabid Baba]

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

[Naazira Badar]

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.

[Aabid Baba]

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

[Ranjeet Kumar]

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.

[alistu]

Hi Ranjeet,

Aside from the aforementioned disadvantages, there are also advantages to it such as lower cost of SOA as well as smaller size of SOA when compared to EDFA and the fact that it can be electrically pumped.

Source:
http://www.fiber-optic-tutorial.com/comparison-of-different-optical-amplifiers.html

Regards

[FAYIQA NAQSHBANDI]

Hi Ranjeet

Yes u are right.The low power requirement of SOAs and low cost makes them very suitable for use as amplifiers in Optical Netwrok units.
Since a large number of ONU units need to be deployed for Next generation networks so to keep the cost of ONUs as low as possible is equally important.Infact now most of these units make use of reflective semiconductor optical amplifiers (RSOAs) which have a lower cost compared to SOAs even.

Regards

[Aabid Baba]

hi Fayiqa,
since you have mentioned that now most of the ONU units make use of reflective semiconductor optical amplifiers (RSOAs) which have a lower cost compared to SOAs , can you please remember an example in optisystem sample files where this reflective semiconductor optical amplifier has been used??
Thanks and Regards

[alistu]

Hi Aabid,

There is a file in the component sample files section in OptiSystem samples named “Reflective SOA.osd”. In this example, RSOA has been used for the purpose of modulating the upstream data into optical domain. I think this is what you are looking for.

Regards

[Aabid Baba]

Hi alistu,
Thank you for your reply . It uuwould be worth having a look into that sample osd file. It can actually help in quite a way. We can have a provision for comparison of performance analysis for a system using a conventional amplifier and using this reflective semiconductor optical amplifier (RSOA). I hope it is a good notice..
Regards

[Naazira Badar]

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

Regards.

[alistu]

Hi Naazira,

Optical amplifiers can be used in such networks. However, I don’t see the point of using OEO amplifiers while access to optical amplifiers is possible for using in the network.

Regards

[Aabid Baba]

Hello Naazira,
are you talking of pure optical amplifiers or reflective semiconductor optical amplifiers??
And can you please explain which other systems you are exactly talking about ??
As far as I am concerned, generally we can use optical amplifiers in any optical network where you want a good performance along good amplification and signal regeneration.

Regards

[FAYIQA NAQSHBANDI]

Hi all

The performance of RSOA (Reflective semiconductor amplifiers ) is quite low compared to EDFAs.SOA and RSOAs are only preferred in applications where in cost is given a higher importance to performance.Since ranjeet is working with next generation networks where a huge deployemnt of Opticak network units already increases the system cost to large extent.So RSOAs are used in place of EDFAs to reduce the cost of these network units although use of EDFAs would give a better performance at much higher cost.

Hope the difference is clear.

Regards

[Aabid Baba]

Hello fayiqa,
Thanks for reply. Well i think you just cleared it to me at least. Actually i was thinking to compare performance of my system using conventional amplifiers and these reflective semiconductor optical amplifiers in future but as you mentioned the performance is not that good so i drop the plan here.But as you rightly said cost effectiveness can be proved using them. Thanks anyway.

regards

[Naazira Badar]

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.

[Aabid Baba]

Hello naazira,
As far as i am concerned , i feel yeah it is the one that can be used in all optical networks. If you check it gives the best performance if you use it in your design and that is what i have observed. Indeed i have used it in my network which is nothing but an all optical amplifier though i didn’t read it anywhere in the tutorial. If you find it please inform here only.
Thanks and Regards

[aasif bashir dar]

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

[Naazira Badar]

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.

[Aabid Baba]

Hello naazira,
As far as optical amplifiers present in the amplifier library apart from EDFAs and SOAs , i have observed they give better results for long range of distances and that too without any distortions in the system but if you try to do same with EDFAs ( setting characteristics same as optical amplifiers) , you would find that the results are not as good as in optical amplifiers because i think non-linearities are more associated with other amplifiers.

Regards

[Naazira Badar]

okay Aabid.
Thanks for sharing.

Regards.

[Aabid Baba]

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

[Manoj Kumar]

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

[Rajguru M. Mohan]

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,

[Rajguru M. Mohan]

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.

[Hamza Ali Abbas Khan]

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

[Hamza Ali Abbas Khan]

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

[Author]

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