CO-OFDM in WDM-RoF

[Duy Le Nguyen]

Hi everyone!

I’m student and I’m making final project about OFDM in WDM-RoF, so i decided to use CO-OFDM. Then, when i design transmitter, i realized that the Quadrature Modulator for radio frequency up converter combined I and Q factors to one output. But the optical modulator of Coherent OFDM require I,Q factors must be separated. So what can i do to resolve it. Please help me.

If i don’t use the Quadrature Modulator, what will i must do to up-convert the signal to radio frequence.

Thanks and regards.

[Gokul Boro .]

Hi Duy Le Nguyen,
In OFDM systems, the IQ modulation in electrical domain is done to generate frequency guard band between the optical OFDM signal and the main optical carrier.
You can ignore this IQ modulation by making changes in the input parallel data to the OFDM block. Using frequency domain hilbert transform and Hermitian Symmetry(available in Optisystem OFDM block), you can design the system without using IQ mixer.

Regards.

[Duy Le Nguyen]

Thank you so much. But i’m using OFDM modulator 12. I can’t find them in it.
And i think in RoF transmitter system, we must convert the signal to radio frequency before sending to optical converter. So, if we don’t use Quadrature Modulator, it still is RoF system??

[Gokul Boro .]

Hi Duy Le Nguyen,
You can upgrade your Optisystem12 to Optisystem14 version. Its simple. You can get a fully functional 30 days trial of the software. If you want a better design you should never use OS12 component. OS12 component has got limited parameters. Try to use newest block in the system.
Regards

[Duy Le Nguyen]

Hi Gokul. Thanks for your reply.

I’m using 14 version, but i dont know about some parameters in new OFDM modul and demodulator.

And can i ask one more stupid question?

The system i attached below is WDM-RoF system, isn’t it?
Because i’m wondering the RoF system must have the radio modulator or not?
I’m making project follow OFDM for Optical Communications
of William Shieh and OFDM modulation sample file im sample folder.

Please reply me.
Regards.

Attachments:

1. Coherent-Detection-WDM-Optical-OFDM-System1.osd

[varinder singh]

hi dey………..
If you want a better design you should never use OS12 component. OS12 component has got limited parameters. Using frequency domain hilbert transform and Hermitian Symmetry(available in Optisystem OFDM block), you can design the system without using IQ mixer.

Regards.

[Duy Le Nguyen]

Hi, vanrider, i know and i will try it. If you have some documents about it, and how to use in new OFDM component. Please send me.

And can you answer the question i ask above?.

Thank you so much.

[Gokul Boro .]

Hi Duy Le Nguyen,
Since you are using Optisystem14 you will get some sample designs in the optisystem samples. If you have not installed the samples, then please install it. The best way to work with this software is to start modifying the sample files available in the optisystem samples.

Even then, if you face problems in setting the parameters, please share your problems here.

Regards.

[Duy Le Nguyen]

Hi everyone.
I’m trying to make my project follow this: http://www.ijircce.com/upload/2015/august/119_Performance.pdf
and the sample OFDM modulatoion in sample folder.
I think it’s ok at the transmitter.
But the result isn’t correct but I can’t find errors.
Someone can help me?

Thanks and regards.

Attachments:

1. WDM-RoF.osd

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