BACKGROUND NOISE FROM ETIs' STAR IS MUCH HIGHER AT OPTICAL WAVELENGTHS
The brightness of a star is much higher at optical wavelengths than at radio
wavelengths. Thus, the background noise from the star will be much higher at optical
frequencies.
Counter Argument
This is true. However, again the issue is not the noise level but the overall SNR. If
the signal can be made much stronger by the increased gain and EIRP of the transmitter,
then the uplink can outshine the star and maintain good SNR.