4 channel WDM problem


#1

Hi Support,

I am trying to simulate a very simple 4 channel demux with the
interconnect. What I would like to see is four channels with 5 nm of
channel spacing. I know what I am doing with a CW laser at the input of
demux is not entirely correct.

Please let me know what is the best way to analyze and simulate this
kind of WDM components. Find attached the test file.

Thanks and kind regards,
Sarvagya
mzis_4_channel.icp (306.4 KB)


#2

Hi @sarvagya_dwivedi,

You can use MZI as a demux, but it only separates 2 channels. Otherwise, you can also use splitters to duplicate the optical signal 4 times and then use 4 filters to separate the channels.

I hope this could help.


#3

Hi Gwang,

Thanks. I have attached the one with directional couplers. Could you please have a look? I want to plot all the channels together with a wavelength sweep of let say 30 nm.

Thanks,
Sarvagya mzis_4_channel_2.icp (1.4 MB)


#4

Hi @sarvagya_dwivedi

I don’t quite understand the second part of your question, you can visualize all the output light power spectrum at the Optical Spectrum Analyzers, however the CW laser is with single frequency so you will get the same centered spectrum outputs.

Your original demux design actually works if you tune it carefully based on the channel spacing; the first MZI should have a FSR equals twice of the channel spacing and the second and third MZI should have a FSR equals 4 times of the channel spacing. Then all the channels will be separated at the end.

Please explain a bit more about your requirement and we will help you from there :slight_smile:


#5

Hi Gwang,

Please find the explanation below:

I don’t quite understand the second part of your question, you can visualize all the output light power spectrum at the Optical Spectrum Analyzers, however the CW laser is with single frequency so you will get the same centered spectrum outputs.
– Indeed you are right.I want to sweep the CW laser for let say C-band, please let me know how to do that.

Your original demux design actually works if you tune it carefully based on the channel spacing; the first MZI should have a FSR equals twice of the channel spacing and the second and third MZI should have a FSR equals 4 times of the channel spacing. Then all the channels will be separated at the end.

  • Thanks. I already did this part, if you check the MZI delay lengths in the file I sent you. I have designed for 5 nm of channel spacing.
    Please let me know if something is not clear.

Thanks,
Sarvagya


#6

Hi @gwang

Did you get time to look into this case? Please let me know if there are any questions.

Thanks,
Sarvagya


#7

Hi @sarvagya_dwivedi,

Sorry for the late reply, I took yesterday off. You can use the Parameter Sweeps platform to sweep the wavelength of the laser source, then add the power spectrum measured by the spectrumeters as results (note that you can add more than one results). Please have a try of this and let me know if you have further problems.


#8

Hi @gwang,

It’s fine. Thank you for your reply. I tried that, but somehow I am getting an empty signal at the output channels at OSA. I have checked in the sweeps–> visualization, I can see 4 channels, However, all the spectrum are showing at one wavelength. Also, is there any way to remove laser peak and see a normalized spectrum?

Find attached. mzis_4_channel_2_sweeps.icp (3.2 MB)

Thanks,
Sarvagya


#9

Hi @sarvagya_dwivedi,

There seems to be a problem in the data collecting stage for the sweep. I will do some more tests and follow up with you.


#10

Thank you @gwang. Looking forward to it.


#11

Hi @gwang
Any news with this?
Thanks,
Sarvagya


#12

Hi @sarvagya_dwivedi,

We confirmed that it is a bug in sweeps. The problem is that, at the data framing stage, to simplify the data structure, only one set of frequency/wavelength data is selected to construct the dataset (it assumes that all the data got from OSA have the same x-axis range, namely the frequency or the wavelength range). However in this case, the OSA always plot the peak frequency in the center and spread through the defined bandwidth; even though the OSA measured BW range for all the sweep points are the same, the actual limits are different. That’s why if you open each of the files in the sweep folder, they all give correct results while the final sweep result in the sweep itself is wrong.

We are working on this problem right now and I will keep you posted about the progress. Thank you for bringing this to our attention.


#13

Thank you @gwang.