What is the bandwidth of the detectors?

[K. Esakki Muthu]

for lower frequencies am getting smooth curves, but for the higher frequencies i am getting diagonally clipped sine waves..why?

[Alessandro Festa]

Which detector are you referring to?

[K. Esakki Muthu]

i used both PIN & APD…but sometimes i am getting Amplitude Modulated Waveforms too

[K. Esakki Muthu]

i hav attched the signal after the detector

Attachments:

1. 

   at-165-GHz.tif
   

[K. Esakki Muthu]

detected signal at 15 Ghz

Attachments:

1. 

   at15G.tif
   

[Ravil]

What is your detector cut-off frequency? Not able to view your attachment…

[Alessandro Festa]

Under the tab “frequency” you can set the bandwidth of the PIN/APD…

[K. Esakki Muthu]

Dear Ravil, i don’t know what kind of image format to upload in this forum?

[K. Esakki Muthu]

Dear Alessandro Festa, thank u …let me try

[Alessandro Festa]

Hi, were you able to have better results?

[Ravil]

esakkimuthu, jpg and png should work. I think you should be able to see it when you go “upload”.

[Ravil]

According to your question, the main reason is the cut-off frequency which you should be able to change with “frequency” tab (as recommended above).

[vipul]

Hi
Simply screen print it and paste it in paint,change type file as .png and save.

[Ravil]

By the way, what version of OptiSystem are you using?

[Heitor Galvao]

Look, I understand what you meant I converted their two images to the jpeg format, and in it I saw what you meant “i used both ODA & PIN … but sometimes i am getting Amplitude Modulated Waveforms too”. At 165-GHz and 15GHz, I would say to you see the global parameters as it was not offered more details of your project or you’re working I created a transceiver (+ external modulation laser + receiver) connected the photodio PIN and APD, and then bessel filter and low was stirring in the cutoff frequency, the here what will change is the value that is being in its cutting frequency, in versions greater than there are optisystem 7 ‘s a variable in the global paramatros called symbol rate, this variable was created specifically for to set the cutoff frequency of electrical filters, there you will vary the value of it, to arrive at a value in a waveform is acceptable in your oscilocospio. If you are using optisystem 7, created a new variable in global parameters then goes in the properties of the photodiodo and in the script of “custom frequency” place 0.75 * (name of the variable that you created) I hope this helps
my compliments

Attachments:

1. 

   at15G.jpg
   

2. 

   at-165-GHz.jpg
   

[Ravil]

Good idea Heitor, but I’m still wondering what scheme exactly did he use then…

[Heitor Galvao]

This working on what exactly?

[K. Esakki Muthu]

Dear Heitor and Ravil, please go through the attached osd file. i am trying to generate millimeter wave using optical frequency multiplication. My input RF frequency is 15GHz using which i am generating 2nd ,3rd,and 4th order harmonics at the detector. if I set the Filter center frequency as 15 GHz,30GHz i am getting smooth sine wave, if i set center frequency as 60GHz and above i am getting distorted/or irregular sinusoidal signal? Why? How to set global parameters? please give me some idea. Thanks in advance to u both. optisystem v12

Attachments:

1. 25.11.14_1.osd
2. 25.11.14_11.osd

[K. Esakki Muthu]

i am using optisystem 12

[Ravil]

Dear esakkimuthu,

Can you attach the pic of your set up from the files you uploaded because I can’t open them with my version of OptiSystem?

[Heitor Galvao]

Sorry I can’t help you I’m using optisystem 7

[Heitor Galvao]

A file of a higher version of optisystem, doesn’t open in a version lower than for example a file of optisystem 12, won’t open in optisystem 7

[K. Esakki Muthu]

hi Heitor,ravil,vipul and festa i thank u all for ur efforts to ans my question. please go through the pic

Attachments:

1. 

   Untitled1.jpg
   

[Damian Marek]

Have you tried increasing the samples per bit in the layout parameters? The bit rate is much less than the frequency of the Sine generator and so the default setting for Samples per Bit may be too low.

[Author]

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