additional CW laser after transmitter

[Dr. Dhiman Kakati]

Hi all,
I have seen in many designs that are available in optisystem 13 examples that after the transmitter an additional laser is added followed by a power combiner so can anyone tell me how it helps to give good results. I have attached the design file herewith. the extra addition of LASER will definitely increase the cost of the system. So please let me know how it is hlping in the design.
Thank you.

With regards

[alistu]

Hi Dhiman,

The additional laser is a white light source, which has a rather wide spectrum. I made the simulation without it and the result got much better! Having this in mind and since the additional spectrum added by this laser has been filtered at the receiver, I think it has been used as a source of noise in this simulation maybe to show the system with DSP can tackle this problem, especially when no optical channel has been used in this simulation.

Regards

[Dr. Dhiman Kakati]

Thanks Alistu its really helpful, Oh then that’s great we can test the system receiver with DSP that is capable of rejecting this extra wide band white light source, its really interesting. you mean here in place fiber fiber attenuation and dispersion effect, the designer have considered the effect of ambient light conditions?

Regards

[alistu]

You’re welcome. The extra power spectrum is filtered by the optical filter put at the receiver front, but some part of it which shares the same spectrum with the CW laser and the main signal has an adverse effect on the signal. What DSP probably does in here is mitigate this effect, which I don’t think can be the same as the undesired effects of a fiber optic.

[Dr. Dhiman Kakati]

oh you are reight. Thanks Alistu for your reply.

With regards

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