Search Results for 'wdm'

[Dr. Dhiman Kakati]

Hello Everyone,
I am looking for some suggestion regarding WDM technologies as I want to work on it, so please anyone suggest what is the trending issue that I can go for implementing WDM and application in present scenario. What I can add from my own to have a good research. I am looking for some best papers regarding this. So I need your suggestion from you who are working in WDM. Also I would like to know about future of WDM or DWDM.

With Regards,
Dhiman Kakati

[Ranjeet KumarParticipant]

Hi mohamed tosson,
i am uploading the osd file of OFDM qam design of different types.
One is 4 user unidirectional OFDM PON system.
Other is OFDM WDM bidirectional system.
As QAM is a sequence generator like NRZ or RZ whose output is given to OFDM modulator and electrically modulated, after it is converted to optical domain by Mach zendher modulator.
Hope this may help you.
Seeking your response.

[Dr. Dhiman KakatiParticipant]

Hi burhan num mina llah,
I tried to modify the 32 channel WDM NRZ system i.e. the ideal one but it was very simple to implement for 4 channel. I did the following modifications.

1. kept all the fiber property constant as before.

2. copied the fiber wavelength and paste in the frequency box i.e. equal to 1550 nm as the fiber.

3. The layout parameter kept constant.

4. the WDM mux and WDM demux modified with the no of channels equal to 4.

5. all the channel spacing and bandwidth kept constant.

please have a look at the modified circuit.

Regards,
Dhiman

[Ranjeet KumarParticipant]

Hi hi nguyan hai ha,
I am uploading osd file of TWDM PON for your use.
Try to simulate whether you could able able to simulate in optisystem 7.
Let me know after i will try to help you.

Seeking your response.

[Nguyen Hai HaParticipant]

Hi aasif, unmer and others kind guys, im so appreciate with your help, it very closed my deadline thesis, but i still only have a litle experience with GPON design. With diagram i know how to show I wil try your guide and let you know soon. But Do you have a TWDM osd same my attach file with 4×2.5gbps upstream and 2.5 upstream and can run by optisystem 7? Sorry for my foolish.

[Duy Le Nguyen]

Hi everyone!

I’m student and I’m making final project about OFDM in WDM-RoF, so i decided to use CO-OFDM. Then, when i design transmitter, i realized that the Quadrature Modulator for radio frequency up converter combined I and Q factors to one output. But the optical modulator of Coherent OFDM require I,Q factors must be separated. So what can i do to resolve it. Please help me.

If i don’t use the Quadrature Modulator, what will i must do to up-convert the signal to radio frequence.

Thanks and regards.

[Ranjeet KumarParticipant]

Hi Fady,
I am here uploading the osd file of Bidirectional OFDM WDM PON.
In this design we have combination wdm and pon using OFDM modulation format.
Hope this prove helpful for you.

[Ranjeet KumarParticipant]

Hi hi nguyan hai ha,
I am uploading different networks design of wdm system with different advanced modulation formats, advanced modulation formats like CSRZ, DRZ and MDRRZ are spectrially efficient and require less power and also used could transmit upto even longer distance.
You can change different parameters like laser power, fiber loops, global data rate , channel spacing and other parameters to see variations in BER and Q-factor and design as per your choice.
Hope this will help you.
We know the latest version is hybrid of TDM and WDM system .
so, i think this to share .

[burhan num mina llahParticipant]

Hi jyoti raina

I have posed a similar query in regards to DWDM system that i was facing. I suggest you to go through the suggestion dhiman kakati has suggested. May be you also would get some idea about your project. I don’t if it will help or not as i myself didn’t implement it yet. Still just have a look. Here i am posting the link of topic..

DWDM system

Regards

Burhan

[Ranjeet KumarParticipant]

Hi Ankita,
In linear scattering, attenuation occurs when optical power is transferred from one mode to another keeping frequency unaltered. There are two categories in linear scattering. They are Rayleigh scattering and Mie scattering. Rayleigh scattering is the main loss mechanism in the visible range. It is proportional to the fourth power of the operating wavelength. Rayleigh scattering loss can be minimized by choosing longest possible operating wavelength. If the size of the defect is greater than one-tenth of the wavelength of light, the scattering mechanism is called Mie scattering. Non linear scattering occurs when frequency is changed during optical power transfer. The two types of nonlinear scattering are stimulated Brillouin scattering and stimulate Raman scattering. Stimulated Brillouin scattering is a cause of concern in long distance systems, in wavelength division multiplexing (WDM) systems and remote pumping of an erbium doped fiber amplifier (EDFA) through a separate optical fiber. Stimulated Raman scattering creates problems in wavelength division multiplexing (WDM) systems.

[Ranjeet KumarParticipant]

Hi Burhan ma’m
First check the CW laser power as being suggested by Dhiman by increasing the laser power to few dbm.
Next vary the tranmsmission channel spacing by varying the frequency of laser, i think standard channel spacing are: 25 ghz, 50 ghz, 75 ghz and 100 ghz. Usually We find difficulty in designing very dense WDM system (channel spacing of 25 ghz).
Check for Wdm mux bandwidth , filter order if you are not using ideal mux.
Now go step by step as Dhiman described above.
Vary no. loops of fiber because for small laser power WDM system gives no results at very large transmission length.
Seeking your response.

Thanks and regards
Ranjeet

[jyoti rainaSpectator]

helo burhan mam.. am using the 32 channel wdm model in optiststem examples..i hv changes channel no to 4 fr my btech project. plz check dat

[Atul SharmaParticipant]

Hello Burhan. Greetings from my side.

I think a relevant question was posted recently not exact the same but it was related to down conversion of the 32 channel WDM system to 4 channel WDM system. You may check the forum posts to find and i feel it will be of great help.

Regards
Atul Sharma

[SAHIL SINGHParticipant]

Hello burhan num mina llah,

I agree with the viewpoint of asif click on the fiber properties and unclick the option of reference frequency…Also as mentioned in the previous comments do make a note of the power at different positions particularly at the WDM mux output.. Hope it helps

with Regards
Sahil Singh

[aasif bashir darParticipant]

Hello burhan num mina llah madam
c;lick on the fiber properties and unclick the option of reference frequency,,,as it will by default take the value for centra frequency.
bandwidth should be constant , CW laser array frequency and power ( as previously), Check frequency (or wavelength) range and f

and as dhimen said
“check power at different positions such as at the WDM mux output, after SMF, after DCF and after the WDM demux, dont let it go high or to low below a certain level.”

with Regards,