Polarisation Multiplexing

[Ajesh Kumar N]

How to do polarisation multiplexing in optisystem?

[Damian Marek]

It’s as simple as modulating two different lasers with two different bit streams. Check out some of our examples like:

100 Gbps DP-QPSK System with Digital Signal Processing

Most of the examples in the Advanced Modulation folder have a variation which utilizes PM.

[Ajesh Kumar N]

Thanks.. Damian Marek for the reply.
Can you please suggest some techniques to reduce crosstalk in WDM systems..

[Abhishek Shrama]

Welcome ajesh!!
Kindly attach your system for more information.I am suggesting a few ways to reduce crosstalk.See if they could help in improving your system:
1) Use appropriate frequency band for transmission
2) Use less denser channel spacing
3) Use broad band amplifier as now HOA’s are used to reduce crosstalk
4) Linewidth of laser you can decrease
5) Use appropriate bandwidth for WDM MUX and DEMUX
Rest make more clear your objectives.
Regards

[Alessandro Festa]

I also add to your points: reduce launch power/channel

[Ajesh Kumar N]

Thanks, Abhishek Sharma and Alessandro Festa for your suggestions. I am a beginner in these fields. Can you suggest me how to measure crosstalk in WDM in OptiSytem 13?(Drawing crosstalk versus Input power graph) Can you please attach some examples.

[Alessandro Festa]

Hi Ajesh, there is no unique way to di that.
For example, if you you could design a system with N channels and change the channel spacing (50GHZ, 100GHz and 200GHz) and see how this impacts the BER at the end of the system. Or you could keep the same spacing, but increase power/channel.

[Ravil]

Hi Ajesh,

Alessandro gave a very good explanation about your point: there is no unique way to define crosstalk dependance. The reason for it is a big vicinity of reasons for the crosstalk to happen: dispersion, nonlinearities, intersymbol interference. However, if you are interested just in crosstalk dependence on input power, you will be measuring the crosstalk that originates from nonlinearties. In general, you should have spectral and BER analyzers/visualizers in each channel on your system.

[Ajesh Kumar N]

Thanks Ravil and Alessandro for the reply. Can you please tell me how to reduce non linear effects using DSP methods and how I could implement that in Optisystem?

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