wdm multiplexer parameters

[Zakarya Saidi]

Hi all ,

Could someone tell me what should I set on as parameters in the wdm multiplexer (especially the bandwidth, depth, frequency and filter order), I know it depends on the type of modulation formats used, but I wanna know how to set an appropriate parameters to get good results, same question for the dwm demultiplexer

[FAYIQA NAQSHBANDI]

HELLO ZAKARYA..
As far as setting parameters of multiplexer are concerned i will suggest you to increase the bandwidth from 10 GHz which is a default value to 20 or more for obtaining good results..i have noticed the same when i increased the bandwidth..
Now as far as filter order is concerned, higher the order more smooth is the response..so i ll suggest you to keep order 4 or more..it also depends on the application as well..
about the depth i will also like to know it..

Thanks & regards

[Zakarya Saidi]

HI Fayiqa,
Thanks for your suggestions. Actually I have seen a paper and it mentions that the bandwidth of wdm multiplexer depends of the modulation format inserted and the bit rate. furthermore, it sets the bandwidth for a bit rate 4*10 gbit/s (4 channels) like
-for RZ modulation B=4*bitrate
-for NRZ modulation B=2*bitrate
-for CSRZ,DRZ and MDRZ B=16GHZ
My question is how does he get this ??
I did the same simulation but I got bad eye diagram in the case of RZ and CSRZ.

[FAYIQA NAQSHBANDI]

HELLO ZAKARYA SAIDI..
Well you have made an important point here..you know it was discussed in some post regarding selection of bandwidth of WDM multiplexer and it was mentioned there the performance gets better with increasing the bandwidth but explanation was given on basis of simulation..the theoretical reason was not mentioned..here i would like to ask u if u can share that paper where bandwidth is set based ob bit rate…

it will be highly helpful..
Thanks & regards

[Zakarya Saidi]

Hi Fayiqa,
Here i’M attaching the paper, please read it and tell me what’s his point here the fact that he is comparing the behavior of some modulation formats with the use of different Amplifiers. I can’t see any contribution here (My opinion).and I couldn’t get the same results
Looking forward for answers

Thanks & Regards,

[FAYIQA NAQSHBANDI]

HI ZAKARYA SAIDI..

Thanks for sharing the paper..I will definitely go through this paper for further information once i get time and shall let you..

Thanks & regards

[FAYIQA NAQSHBANDI]

Well just went through the paper.. you are right.
What he has done is that he has compared results for various modulation schemes ( NRZ, RZ , CSRZ , MDRZ ) for various data rates.. he has used different amplifiers as he has mentioned in each case and calculated for the results.. he has done comparison on bases of amplifiers but as for as selection of bandwidth for multiplexer is concerned , he has not mentioned any reason why he has done that.. i don’t know what possibly is the logic behind this. I hope someone helps on this.
Thanks & regards

[Naazira Badar]

Hi all..
I have checked my results on values less than 10 Ghz , and results were seen to be improving.
I had checked on 8 channel wdm system. I’m still not sure how this bandwidth parameter of wdm mux/demux affect performance.
It would be really good if this thing gets clear.

Regards
Naazira.

[FAYIQA NAQSHBANDI]

HELLO NAAZIRA..

well what i understand here is that you are getting contradictory results to that of mine.. i got results improved when i tried to increase the bandwidth of the multiplexer..
i was also discussed before when alistu had started the discussion.. i hope it gets clear soon because itbhas an impact on the results also.

Thanks & regards

[Naazira Badar]

Yes Fayiqa Naqshbandi..

yes i know. In fact I myself had a case where in results improved by increasing the bandwidth as well.
Since I have had both the cases, I have not been able to conclude about the exact impact of varying this bandwidth value.

Regards.

[Zakarya Saidi]

Hi Naazira Badar and FAYIQA NAQSHBANDI,

the problem is not increase or decrease the wdm bandwidth for getting better results (no rule for that). From some of my experiences, this variation depends on the modulation scheme used and also the length of the fiber…

with Regards

[SAHIL SINGH]

Hi all,

I agree with fayiqa naqshbandhi that the results improved when you try to increase the bandwidth of the multiplexer…. And i want to ask Zakariya here that is there any logic on the basis of which you suggest that this variation depends on themodulation scheme used or the lenghth of the fiber ? Please provide the explanation (if any)…. Hope to hear from you

Thanks and regards

Sahil Singh

[Zakarya Saidi]

Hi SAHIL SINGH,
I got this from some simulations that I have done before , but I would also know if there is any theoric explanations about that.

Regards.

[SAHIL SINGH]

Hi Zakarya Saidi,

Indeed i guessed this correct that you concluded on the basis of simulations that you have conducted… Do you have some theoretical explanations ?

Regards

Sahil Singh

[Ranjeet Kumar]

HELLO ZAKARYA,
For wdm mux we could have the following parameters values as:
Frequency 193.1
Frequency spacing 100
Bandwidth 100
Insertion loss 0
Depth 100
Filter type Gaussian
Filter order 2

While for WDM demux we should have following parameters values as:
Frequency 193.1
Frequency spacing 100
Bandwidth 100
Insertion loss 0
Depth 100
Filter type Gaussian
Filter order 4

Here i am attaching 8 channel CSRZ WDM SYSTEM.

[Dr. Dhiman Kakati]

Hi Ranjeet Kumar,
this example is for basic intensity modulation, Did you try for advanced modulation schemes such as DQPSK in one of the topic started by Urvi pathak, I have tried approximately all the possible ways still not getting an appropriate results in terms of Constellation and Eye diagram. Thanks in advance.

Regards,
Dhiman

[SAHIL SINGH]

Hello Ranjeet Kumar,

Thanks for such a valuable information… Your efforts are highly appreciated…

Regards

Sahil Singh

[Zakarya Saidi]

Hi Ranjeet Kumar,
Your osd file attached is 8 channel RZ wdm system and not CSRZ. please check it again and let me know if I’m wrong.

Thanks

[Ranjeet Kumar]

You are welcome Sahil Singh.
Thank you for your kind consent and appreciation

[Ranjeet Kumar]

okk Sahil Singh, you are most welcome.
I will try to share the valuable information as per my ability.
nice to steal the appreciation and discussion which boost the confidence.

[SAHIL SINGH]

Hi Ranjeet Kumar,

You are indeed welcome and i hope you share your valuable knowledge to help the other members of the forum… Once again i appreciate you for your worthy efforts…

Regards

Sahil Singh

[Ranjeet Kumar]

Hi,

Main parameters of Wdm system as :

Main parameters Standard Isolation High Isolation
Configuration 1×2, 2×2
Spectral bandwidth, nm (1295…1325nm/ 1528…1565nm)

Insertion loss, max, dB 0,3 0,7
Excess loss dependent on wavelength and temperature, max, dB 0,3 0,3
Isolation, min, dB 17 34
PDL, max, db 0,1 0,2
Directivity, min, dB 55 55
Optical power, max, mW 500 500
Operating temperature range, °C -10…+60 -10…+60
Fiber type SM Corning SMF-28 Corning SMF-28
Housing dimensions/fiber diameter, mm Ø3.0 x 55/ 0.25mm; Ø3.0 x 55/ 0.9mm; 6,4 x12 x 96/3mm

These are different parameters of WDM Mux.

[Ranjeet Kumar]

Hi,
For wideband WDM system, we have:

wideband WDM based on fused type 1×2 splitter joint with isolator;
equipement allows two-directional optical transmission on one fiber in 1310 or 1550 band, with standard OLT in PDH and SDH systems (STM4 inclusive);
main parameters:
◦ bandwidth 1310±20nm or 1550±20nm;
◦ insertion loss (for one pair) < 8dB;
◦ channel isolation > 32dB;
◦ operating teperature range –5…+70°C.

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