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| Full Name | UMAR FAROOQ |
| Organization | National University FAST |
| Job Title | Student |
| Country |
Forum Replies Created
Hi,
Thanks for your reply.
Here are the main Parameters.
Length of fiber= 25 Km
Bit Rate= 5 G Bits/s
No of OFDM Carriers =16
Each carrier has 16 QAM Modulation
This setup is converged with 60 GHz millimeter wave carriers and then after fiber these carriers are detected on OFDM receiver. Its a direct detection system.
The setup works fine for btb and upto 5 Km but when I increase the fiber I got the very bad constellation.
Now I want to compensate this dispersion with DSP code file.
Best regards,
Umar Fraooq
Hi,
Thanks for your reply. Yes the major cause is dispersion. I somehow made the DCF while reading some research papers about commercially available DCFs. After putting the parameters somehow setup works. But when I disable the DCF again constellation becomes worst. But still I am unable to understand either these parameters can be used in PON configurations.
What are your thoughts that the DCF parameters are separate for PON configurations and separate for all other configurations. Or in short there is separate DCF for PON and separate DCF for other setups.
Regards,
Umar
Thanks for your suggestions i will make changes and when when i got my desired results i will share in forum.
Line width 0.2 MHz,Gain of amplifier 20 db,launched power 0 dbm. At ONU, a 3dB optical splitter divides downstream into two parts. An
intensity modulation technique of 10-Gbps OOK is used to re-modulate the first half of the power splitter to generate upstream data signal while the second half goes to DQPSK OR DPSK receiver.This re-modulation takes place by the received downstream signal which is either DPSK or DQPSK. I know its hard to understand but currently i am working on this project and it is not possible for me at this time to upload simulation.
just see my eye diagram and tell why one eye coincide with another eye as i have clear eye opening on up streaming side.
According to your suggestions i use optical amplifier and change the input power but my eye diagram remains same.Upstream eye diagram is fine but downstream eye diagram remains same when i use DQPSK at transmitter.When i use DPSK its all fine but reach is limited.
I use DCF but it made no change same problem exists.
Actually i have to calculate the power budget of my whole system.I have 4 channel wdm system on transmitter side i applied DQPSK modulation format after multiplexing then i have 50 km SMF link then WDM DEMUX after that i use power splitter one signal goes towards DQPSK receiver and the other to RZ OOK Transmitter for remodulation then these 4 remodulated signals are multiplexed and then SMF then DEMUX and then to OOK receiver and BER analyzer.I use DQPSK in downstream and OOK in upstream for the calculation of my power budget and this eye diagram is on DQPSK receiver side.
Please suggest which modulation format is good for long range PON and what are the improvements possible in this sytem.
Regards
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.
Attachments:
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.