Search Results for 'wdm'

[kollParticipant]

Sorry question below:

1) What will happened to the amplification and noise properties of the WDM channels if EDFA is used simultaneously to amplify multiple WDM channnels span over the gain wavelength range of the EDFA?

[koll]

Multiple WDM channel and the used of EDFA

[Alessandro FestaParticipant]

Hi Alitsu, ok I understand your point.
For WDM cases, I usually do not use Constant Dispersion parameters, but I use Disp vs wavelength from one of the files built-in in Optiwave.
You can try to use one file for the propagation fiber dispersion, and create the one for the DCF by simply multiplying each dispersion number * (-5). This should improve your simulation.

Let me know if this works.

Alessandro

[alistuParticipant]

Hi Alessandro,

Unfortunately, I cannot share the whole project file. I have only sent the fiber link so as to let you know of fiber characteristics. I have used a WDM-OFDM system, but it is not really important, since the problem has something to do with fiber dispersion and must be there in any WDM system with the specified channel spacing that uses the same fiber link. Thank you for your consideration.

Regards

[Alessandro FestaParticipant]

Hi Alitsu, your project file seems to be corrupted, when I open it I can only see the orpopagation fiber, but not the input WDM signals…can you posti it again?
I hope I can help you.

Alessandro

[alistuParticipant]

There are some components such as controlled pump laser that can be controlled in some way. You can find them in “Optical Sources” section in transmitters library and you can read more about their function in their help section. As for the filters, I suggest you visit the following Optiwave link introducing optical filters:

WDM Components – Tunable Filters

Regards

[Saad Zafar]

Hello.

I want to develop a WDM System with tunability option in it. As initial step, I want to learn how to implement/simulate Tunable laser and tunable filters . Your help in this regard would be highly helpful for me.

Thankyou

[alistu]

Hi all,

I have implemented a WDM system using OptiSystem. When I increase the bit rate (and therefore I have to increase the channel spacing), the channels that are further from the optical fiber reference wavelength have worse constellations than the channels near the fiber reference wavelength.

I have attached a screenshot from the WDM spectrum after the fiber link as you can see. I have also attached an image showing constellation diagrams of an eight-channel WDM (channels one to eight, from left to right), while the fiber reference frequency is the same as the central frequency of simulated band. As you can see, the signal is more corrupted as the channel as farther from the central frequency of the fiber, even though I have used a DCF in the line.

I would like to know why this signal degradation is happening while I have used a fiber as DCF with the same characteristics and when the dispersion becomes noticeable in the main fiber, dispersion in the second fiber with the same (yet negative) slope and dispersion value should compensate for it. Am I right?

Thank you all in advance.

Regards,
Alistu

[alistuParticipant]

Hi Dhiman,

Optical add-drop multiplexer is a component that can be used in WDM systems. In WDM systems, different channels have different wavelengths, are multiplexed in transmitter using WDM multiplxer and can all be demultiplexed at receiver. Sometimes it is desired to access or “drop” the information of one certain channel before the end receiver and/or add a new channel there. In these cases OADM can be used. You can find some examples in OptiSystem samples in “Add and Drop” folder.

Regards

[nadzreen]

Hi All

I run EDFA characterization sample and dual port WDM give result at all specified wavelength.But my amplifier did not show any reading at certain wavelength.My wavelength start from 1880nm-1950nm. why this happen? attached is my design.thank you.

[Prarthana KashyapParticipant]

Oh then I can meet any specification that are available in the market by adjusting the parameters of WDM interleaver MUX/Demux but putting the appropriate centre frequency and respective required spacing.

Thanks.

[alistuParticipant]

Hi Aabid,

I believe it would be quite helpful if you take a look at the examples in the OptiSystem samples regarding the aforementioned. You can find these three samples at OptiSystem 13 Samples\Component sample files\WDM Multiplexers Library\Add and Drop. One is related to WDM add, one related to WDM drop and one WDM add/drop. Please see if they are useful and ask any further questions you might have.

Regards

[alistuParticipant]

You’re welcome. There is no such component in the OptiSystem library and there is no need for it, since the available components named “WDM interleaver mux/demux” can act as one provided that you choose the proper channel spacing properties and so on. This component can correspond to any channel spacing you set.

[Dr. Dhiman KakatiParticipant]

Hi lavanya, I am giving you some theoretical concept why the ISI occurs in WDM system, You may find this helpful.

one of the reason for ISI in wavelength division multiplexing is due to the less channel spacing, i.e. less difference in wavelengths or frequencies and at a high data rate transmission. On way to reduce the intersymbol interference (ISI) is to use return-to-zero (RZ) format in place of Non Return to Zero (NRZ) format. The RZ format in optical communications has advantages over the more frequently used non-return-to zero format, mainly because the RZ-modulated signal can withstand better the impact of fiber nonlinearity and polarization-mode dispersion. the most widely used method is the polarization interleaving method. However, for the very small channel spacing, the power leakage from one channel to its adjacent channels still remains. To reduce this leakage, one need to use filters with sharp spectral response, typically consisting of more than one stage- such filters are expensive, exhibit high insertion loss, and often cause large intersymbol interference (ISI). the adjacent channel interference (ACI) can be reduced by the dispersion interleaving method. these are the two methods- POLARIZATION INTERLEAVED & DISPERSION INTERLEAVED WDM SYSTEMS. you may find so many papers on these two topics on the internet.Once you make the design you have to see which method will be fruitful for you.

Regards

[lavanya krishnan]

how can I reduce isi in a wdm system?