why different gains

hi umar syed
I think the total gain should be the same, if the total input powers are the same for both cases.
Did the power of your single carrier match the total power of your multiple carriers combined?
If not, you may have seen gain saturation…

Did you do simulations or experiments?
If simulations, are all your carriers modeled as CW sources (without linewidth), or did you consider them to have a certain bandwidth?

Hope that helps somewhat, with reagards

hi umer syed…
i totally agree with aasif bashir dar that the total gain should be same.
As far as gain of the EDFA depends on many parameters such as EDF length, pump power, operating wavelength etc. EDFA gives different gain at different wavelength because of strak split in the energy band of EDF which led emission at range of wavelengths (C-band or L-band).  Gain is relatively flat in L-band compare to C-band, however, value of gain is higher in C-band compare to L-band.
hope your problem gets solved
with regards

HELLO UMER SYED..

I also agree with aasif bashir dar here that the total gain should be same…As far as gain of the EDFA depends on many parameters such as EDF length, pump power, operating wavelength etc. EDFA gives different gain at different wavelength because of strak split in the energy band of EDF which led emission at range of wavelengths (C-band or L-band)…
Gain is relatively flat in L-band compare to C-band, however, value of gain is higher in C-band compare to L-band… I hope it will help you.

thanks & regards

Hi Umer Syed. Greetings from my side.

Actually I did not get your query at first but with what Aasif Bashir Dar explained i got what your query was at first place. I agree with him saying that the total gain should be same.
As far as gain of the EDFA depends on many parameters such as EDF length, pump power, operating wavelength etc. EDFA gives different gain at different wavelength because of strak split in the energy band of EDF which led emission at range of wavelengths (C-band or L-band). Gain is relatively flat in L-band compare to C-band, however, value of gain is higher in C-band compare to L-band.

Regards
Atul Sharma

you are welcome umar syed, greetuings and cheers

Hi Umer Syed,

I totally agree with aasif Bashir that the overall gain of the system should be same… Whereas the gain of EDFA depends on length of fiber and wavelength in particular…Also as mentioned by Atul Sharma EDFA gives different gain at different wavelengths…

Regards
Sahil Singh

hi umar syed,

as mentioned by alll, gennerally we use EDFA as the main amplifier along the fiber link..but the gain of EDFA depends on both length of fiber and wavelength in particular..
use of raman amlifier (which has nearly equall gain for all wavelength)is usually restricted to the rx end, but it amplifiers the signal by large amont can cause fiber non-linearities ,if used before fiber.

wirh regaerds

Hi umer syed

Very well explained by aasif bashir dar.. Aasif will you please specify or i would say explain a bit more about the difference in gain in the two different bands respectively L and C band as is already asked by umer syed.. That would be helpful for all of us as there might be a genuine reason for this difference of gain for sure. I intute that there should be a reason for different gains in two different bands.. Please provide the response

Regards

Burhan

Hi Umer syed,

It is a very interesting question raised by atul sharma that how are you implementing this back up fiber in optisystem ? I too am eager for your response.. Hope to hear from you soon

Regards
Sahil Singh

Hello Umer Syed,
The above mentioned posts have clearly given you an idea about different perspectives now. I hope it will help.
Regards

Hi Umer,
Could you please explain the terms Single source and multiple source in your design.
What does it mean in optisystem.
Seeking your response.

Hi Ranjeet,

Infact a very nice question posed by you about Single source and multiple source.. Hope to hear from umer syed…

Regards
Sahil Singh

Hi burhan num mina llah..
Well I think since the gain is wavelength dependent, so it would certainly be different in different bands like C and L ..because they operate on different wavelengths.

Regards
Naazira Badar.

Hi Naazira badar

thanks for the information that is ofcourse the reason… here i guess its in the same band but the problem is between the number of sources whether it is single and multiple and likewise does the gain differ..

Regards

Burhan

Hi Ranjeet

I believe what umer syed is referring to hear is that we have single source as for example CW laser and as multiple sources we have an array of CW laser or we can say WDM Transmitter containing multiple sources…

Regards

Burhan

I understand that Burhan num mina llah..but even if we use the same band, but multiple sources, we use the different wavelengths. so i think the same logic should apply.

best wishes
Naazira Badar.

Hi Naazira Badar

yeah that could be the reason for sure… different gains for different wavelength..but here as you can take a look at the query posted again that he has mentioned that at the same wavelength.. does it still happen on same wavelength..??

Regards

Burhan

Hi Burhan num mina llah.. and Hi Umer syed..

I am presuming that by multiple sources, you mean multiple CW LASERS.. but I don’t understand why would you transmit using the same wavelength from all the sources at the same time?! This would result in wavelength interference…and that could be a reason that at the EDFA output, different gain is achieved than in single source case. Please correct me if I have understood the query or the concept wrongly.

Best Wishes
Naazira Badar.

Hi Naazira,

I too agree with your view that when you transmit using the same wavelength from all the sources at the same time that would definitely lead to wavelength interference.. Very well pointed out..

Regards
Sahil Singh