How to form Simulation model of WDM PON using downstream DQPSK & OOK upstream

[UMAR FAROOQ]

I have to make a WDM system in which 4 wdm channels are used and i have to use DQPSK modulation format to make my transmitter.And also how to design DQPSK receiver so that one half of the signal is send to the DQPSK receiver and the rest of the downstream optical signal is re-modulated by an intensity modulation technique of 10-Gbps RZ-OOK. The generated upstream signal is transmitted back to the OLT using SSMF through a complete path. How to make this system?

[alistu]

Hi Umar,

Welcome to Optiwave forums! Could you please attach the paper you are trying to reproduce, as there is remodulation and more information might be needed? Since you seem to be new to Optisystem, I strongly suggest that you go through Optisystem samples on multi-access systems to get insight about how to implement PONs. This might be quite helpful to you.

Regards

[Ravil]

Hello Umar,

As it was mentioned before by Alistu, the reference on paper with the scheme that you are trying to implement is highly recommendable. At the same time, could you, please, attach the scheme itself? As I understood from your description, you are planning to use different modulation formats for down- and upstream. However, what did you mean by “one half of the signal is send to the DQPSK receiver”?

[UMAR FAROOQ]

Yes i am planning to use different modulation formats on transmitter side and would make a WDM system.From this i want to compare different modulation formats and see their results.
one half of the signal is send to the DQPSK receiver means that i am using power splitter at the receiver side “one half of the signal is send to the DQPSK receiver if i use DQPSK modulation format to make DQPSK transmitter while the second half of power splitter is re-modulated by OOK(on off keying) and send to the OLT.Last step is that i want to calculate power budget of this scheme.

[Ashu verma]

Hi!Umar farooq
Welcome to optiwave,Attached paper can be implemented in optisystem.You can also takre help from optiwave samples of wdm pon,which ,in turn gives you the basic idea of how does wdm pon works .you can make changes in sample file such as change OOk to Dqpsk and receiver at user end.in this way you will get two sihnals at 45 and -45 .Yoi can use one of then as user signal detected and other one circulate and reuse it for upstream.Hope it would help you ,i will also provude you some links of similar discussion and topic which discussed here in forum containing setups too.

[Ashu verma]

Kindly visit these kinks for detailed information.Once you get to knoemw the system working.It would be easy to implemnt ehat you trying to do

Eye Diagram obtained from PON using WDM Mux

Dowload setups and try to simukate by own and nake changes into it.If you will find any probkem ,you can share with us .

[UMAR FAROOQ]

Thanks sam for your reply.Can you please tell me which modulation format is best regarding WDM system for better reach and other considerations i want to improve the system by designing transmitter.I used DPSK modulation format at transmitter side and got good results now please tell how can i further improve the system? Please see the attached paper.

[Ashu verma]

Welcome,since you are asking about best modulation format then i would suggest you the DQPSK.However now all the modulation formats are like NRZ RZ DPSK MDRZ etc are provide different results and performance in different systems.Moreover you can try them by your own.lot of article you find on net regarding these formats and it is hard to find only one format to use which comes out best because different papers has differebt modulation format best according to scenario.For example if you kept non linearities off then Dpsk performs best and csrz mdrz also provide good results than Rz Nrz due to less prone to dispersion and are bandwidyh efficient .But where you consider non linearities ,trend become opposite ,here Rz performs better due to less prone to non linearities but yes more dispersion and bw requirements.So there is trade off between these .As i have seen many papers on PON and maximum use DQPSk has been analyzed for NG PONS .

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