Problem with the Digital optical switch

[Raja masud]

Hi everyone

I am trying to use the Digital Optical switch as a modulator, which modulates the CW laser, but it seems that it is not working. Anyway I know the MZ modulator, which can be used instead of the switch, but it need electrical signal, so I want to use the switch a modulator, which do not need electrical signal. I want know my mistake in simulation. so someone help me to find it out.

I have attached the osd file of optisystem-7 and a PDF file.

Thank u all

[Raja masud]

OSD and PDF file is here

[alistu]

Hi Raja,

I implemented the same simulation in Optisystem version 13.0.3 and was faced with the same problem… Strange problem with such a simple structure.

Here’s a link I have found of the same problem, but since some issues were discussed in private, it doesn’t help much:

optical switch

[Alessandro Festa]

Hi Raja, as alitsu point out, since the topic has been already discussed probably the best thing to do is to contact Damian for help.

[Damian Marek]

Yes these switches are very limited and something we are working to change. They will only act on the first bit transition and not as a real dynamic switch should. In the meantime you could build a switch yourself out of more primitive components.

see the attached example

[alistu]

Thank you Damian. But the digital optical switch was supposed to have two inputs and based on the drive bits, it should pass either signal from the input1 to the output 1 and input2 to output2 and vise versa. Your example doesn’t do such a thing; it just transfers the only input’s signal to either of the outputs, right?

[Damian Marek]

Ah yes you are correct! However, the main idea was to show that you can make switches with components already available.

[Raja masud]

Hi Damian Marek

I have made your switch. It is working fine with any combination of bit sequence of User Defined Bit Sequence Generator but except for all 1s or all 0s. How to make it work for all 1s or all 0s?

Raja

[alistu]

Hi Raja, It seems to me that the switch implemented in the file attached does not work the way it is meant to, even when the bit sequence is neither all-zero or all-one. Please have a look at the attached image which shows visualizers for 0001 user defined bit sequence. Is it true? Thank you.

[Raja masud]

Hi alistu, the switch work for 0001 but it did not work for 0000 or 1111 combination. can you make it work?

[alistu]

Sorry Raja I am already confused with the system performance. Does the image attached show the desired result you want to get from the switch you have implemented? If so, I would be grateful if you kindly explain how you explain in what way it represents the ‘0001’ bit sequence I have used in PRBS. Thank you.

[Raja masud]

hi alistu

Did you see my attachment? in attachment you will see that, this switch work fine for any bit combination except 000000000000000 or 1111111111111111.

[alistu]

Of course, and the image I have attached belongs to the situation when the input to your attached osd optical switch is 0001. Can you please take a look at my reply #24046 and tell me how the signal shown in the visualizer corresponds to the sequence 0001? (I entered 0001 in the above switch in your layout)

[Raja masud]

Hi alistu,

I think you did not understand my question. PLZ first understand then reply. I do not need 0001 combination,this “0001” combination work very well by this switch. i said that, when i put 00000000000000 and 1111111111111111 in the user define bit sequence generator then both the output ports of two switch display 50fW powered steady line, but for a switch, one port should display 1mW and other port should display 0W. And my question is why they act like this? What is wrong with this switch?

[alistu]

Hi Raja, Actually I believe you didn’t exactly get my point! I know you only have problem with all-zeros and all-ones conditions, but I was implying that the “0001” condition does not give an answer according to your post #22908, so I wanted to know how you interpret a signal as the RIGHT ANSWER for your system. I’m not saying it certainly works wrong, I just want to know how you interpret it as RIGHT.

[Damian Marek]

I understand this problem you are experiencing and I don’t have a very good answer! From my understanding the “0001” part works fine. It repeats because the defined sequence is only 4 bits long while the simulation lasts for 16 bits. The User Defined Bit Sequence Generator then just repeats the sequence.

As for the problem in the case of “1111” or “1111111111111111” if you prefer and the opposite case, this must be a bug and I don’t think there is an easy fix for it. I have notified the OptiSystem team about, so hopefully we can get a fix out soon in the next release. In the meantime, are the cases “1111” and “0000” absolutely necessary for your simulation?

Damian

[alistu]

Thank you Damian for addressing my question. So there remains Matlab component in case of necessity.

[Raja masud]

Hi Damian Marek

Thanks for your answer. And You again 100% got my point. Yes this is need for my simulation but i have solved it few hours ago. and i have upload it here. but i have got another problem. when i connect my binary source{which i also draw in simulation} to my switch instead of “user define bit sequence generator”, warning is generated.

Now my question is why this is happening? How can i stop warning? PLZ answer my question.

Thank you again

RAJA

[Damian Marek]

Replace those Binary Delays with Delays found in Signal Processing Library/Logic/Binary. The Binary Delays is a simulation tool for running loops or bidirectional simulations and not what you want here. Keep the signal iterations at one, again because there is no feedback portions or bidirectional sections. I got the simulation to output all 1’s from the Binary XOR, which is correct since both inputs are 1’s.

Damian

[Raja masud]

Hi Damian Marek

I am trying to make a binary bit generator that generate 0s for first 20 iterations, then it generate 1s for next 10 iterations and then it generate again 0s for rest of the iteration. Now without the binary delay how can i make such thing? PLZ suggest me.

However i have made such thing which generate electrical signal. I have attached that file. but when i used it as an electrical signal generator with an modulator, the modulator did not work properly. I hope you will see that file.

Raja

[Damian Marek]

Couldn’t you just import a text file with the bit sequence of 20 0s and then 10 1s, followed by the remaining number of 0s.The problem with the time delay is that it shifts the entire signal through the time window, but the signal loops through the time window and comes back to the beginning again. So a signal with all 1s shifted in time will still be a signal of 1s.

You could get more complicated and create a bit sequence with 30 1s and then all zeros with a suitable time window and use a time delay on that, but in that case I think using a text file would still be simpler. I made this project in OptiSystem which works except the looping causes an additional peak to form.

Regards

[Raja masud]

Hi Damian,

i can’t open your attached osd file in my optisystem-7

[Raja masud]

Hi Damian Marek

Can it be done? PLZ help me to solve this problem

[Raja masud]

Thank u Guys, thank u everyone to your valuable answer.

I think there is an option to create component by the “MATLAB component”. So if Optisystem can create switch by matlab component and upload it, then it will be very helpful.

Thanks again

[alistu]

It might tame some time to make a digital optical switch with Matlab on your own, but it is not that hard. You just need to learn about optisystem electrical, optical and binary structures first. Use optisystem tutorials and videos on youtube for the start. Then all that remains is just a simple matlab program that first checks the drive bit value. Then according to the logical value of the bit, it decides the two outputs for the next N samples (when N is the number of samples corresponding to the duration of one bit in the drive bit sequence).

[Raja masud]

Thanks to Alistu,

Actually, I am trying to work with the MATLAB component, I have seen those video on the youtube and in the archive of OPTISYSTEM, Since Optisystem is new to me and i need to learn MATLAB again, so i think it will take little more time to build a component. So in the mean time if someone create this switch PLZ do share.

[alistu]

You’re welcome, Raja massoud.

I am pressed for the time right now, otherwise I would have done this for you. But as far as my experience can tell, you’d better start creating the Matlab component yourself no matter how much it might take up your time rather than rely on the others in the forum or you have to wait for several days. Unless of course the Optiwave team has the component.

Cheers!

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