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Optiwave software can be used in different industries and applications, including Fiber Optic Communication, Sensing, Pharma/Bio, Military & Satcom, Test & Measurement, Fundamental Research, Solar Panels, Components / Devices, etc..
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Optiwave software can be used in different industries and applications, including Fiber Optic Communication, Sensing, Pharma/Bio, Military & Satcom, Test & Measurement, Fundamental Research, Solar Panels, Components / Devices, etc..
Download our 30-day Free Evaluations, lab assignments, and other freeware here.
how to draw pure constellation in I-Q modulator. Mine is always so many spots.
Make sure your oscillator (CW Laser ) has a small linewidth. For a perfect system set it to 0, realistically I think nowadays a linewidth of 0.1 MHz is not unreasonable.
Good luck!
Hi Damian,
you mean we should keep 0.1MHz at CW laser?
my schema has CW laser with 0.1MHz. I will add fiber and receiver to my schema.
Phase noise is what causes that wander of the constellation diagram, so using a laser with a smaller line width will eliminate that problem. Try a linewidth of 0 and you will get “perfect” results, although physically it might not be accurate.
Is you constellation after the signal passes in an optical system?
No, just after modulation. I didn’t add amplifier and fiber.
But actually after added fiber(50km), my constellation became to just crowded thing in central. how to fix it?
What kind of modulation are you applying?
I’m trying to apply 16QAM.
after transmitter, connected to amplifier and Gaussian filter then 50km fiber, then amplifier and filter.
After second filter, I checked 16QAM coherent Receiver and Constellation Visulaizer.
but result is like attached.
It should be possible to transmit the signal over 50 km of fiber with low distortion of the constellation. Maybe you have a filter or component that is set to the wrong values. Can you attach your project file?
Hi Damian,
please check attached project. i created 16APSK signal after modulator. But After fiber and amplifier, constellation is very bad. is there any way to keep constellation as possible? what components was wrong ?
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