FILTER

[Aabid Baba]

Can we use a filter in sweep mode??? does it work properly??

[aasif bashir dar]

well aabid

which filter u are reffering to?

[Aabid Baba]

any optical filter? say , optical low pass Bessil filter

[aasif bashir dar]

yes ofcourse,u need to set sweep mode for wavelength in the window that appears on clicking on the filter.then set the different values for the wavelength

[Aabid Baba]

thank you asif! much appreciation.. i am actually using a fiber bragg grating.. and i want multiple wavelengths to be reflected back, so i thought of using it in sweep mode..
one more thing! can you please tell me if we can use fiber bragg grating in both directions of the signal flow..say in add/drop we we use it both directions but in optiwave it is one directional…we cant use it as an sdd/drop here…!

[aasif bashir dar]

well aabid ,

in optiwave we probably do not have such provivision of using single grating ,so that we can implement the add drop multiplexer.

however as per my thinking u can use two FBGs with similar parameters for such design (one for each adding and dropping a wavelength respectively)

[Aabid Baba]

thank you asif for the reply.. but in optiwave 14 , we do not have such provision yet..what we have studied in theory papers , it is not same while implementing here in optiwave..!
if you take an example of an add/drop mux implemented by a fiber bragg grating ,theoretically YES, we can implement it but however in optiwave the fiber bragg grating provided is uni directional and can reflect only in one direction ( drop function). for add function , we can’t cascade two gratings as you are saying.. Optiwave must provide with bidirectional FBG so that it can be used for drop & add function simultaneously.. Hope you got me!

[alistu]

Hi all,

In addition to what Aasif mentioned about add drop multiplxers using two fiber bragg gratings, I think it would be worth looking an explanation provided earlier in this regard (which I think might be implemented using Optiwave):

ROADM in DWDM network

Regards

[Aabid Baba]

Thank you Alistu.
This was what i explained to asif in the above comment. Theoretically, it is possible but in optiwave we just cant implement it..For that, the fiber bragg grating should have been bidirectional. Optiwave 14 does not provide us with this option..
Anyway, thanks for your help.

Regards

[alistu]

Can you please elaborate more on the reason as to why it is not currently possible? The current Fiber Bragg Grating components available in OptiSystem have three ports, one input and two outputs, and it seems to me this should be enough for the function suggested in the image I had attached.

[Aabid Baba]

Hello alistu!
yes i agree , no doubt it has three ports ( one input and two output ports) but if you try to cascade two fiber bragg gratings for add function , you simply cannot..
It would be easy for you to understand if you do it on optiwave.. Let me put it this way, say you do cascade two fiber bragg gratings, at the first output (transmittance side) of first fiber bragg grating you will be having a signal with three signals with high power (transmitted signals) and on the second output of the first fiber bragg grating you will have the reflected signal (dropped signal) with high power and other three with low power..Now, at the input of the 2nd fiber bragg grating which is the cascaded , we will have the signal from the first output of the first fiber bragg grating.From this signal at the input , we can only drop a wavelength. There is no way that we can add another wavelength.
Hope i answered your query.

[alistu]

Thank you very much for your explanation. I think I am getting your point. However, what about using an ideal MUX between the two FBGs? The ideal MUX only adds the signals and has two ports: One for the signal coming from the first FBG, and one for the wavelength we would like to add. And the output of MUX is connected to the second FBG.

[Aabid Baba]

yea Alistu we can use a MUX for adding a signal but then 2nd FBG will be rendered useless in the system design. For that matter , optiwave 14 itself contains an add/drop module. But i wanted FBG to act as add drop multiplexer because it provides me with what my requirement is.

[alistu]

That’s right. The component is also available in OptiSystem 13. However, I was discussing the case Aasif was discussing. Otherwise, if you consider my link you’ll notice the structure available with one FBG. Othewrwise, when the component is available, the discussion may seem useless to some.

Regards

[aasif bashir dar]

yepp we can not make an add drop multiplexer using an FBG as shown in below figure.

itz very unfortunate…
because in optisystem we have FBG with three ports….

[aasif bashir dar]

here it is;

Attachments:

1. 

   OADM_module.png
   

[Aabid Baba]

asif yeah!
we can use it just as a filter now rather tuned filter.
thank you for your participation.

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