Auto-Compensating Polarization Changes with Mirror/Reflector and Faraday Mirror

[islahna]

Hi,
I read several literatures on quantum cryptography plug and play system. I found out that Faraday mirror was used to compensate polarization fluctuations. Photons are reflected orthogonally by Faraday mirror and their polarization changes will then be autocompensated, provided they follow the same path (same fiber). I'm thinking if we use a Mirror/reflector, will polarization changes be auto compensated as with Faraday Mirror ? Is it necessary that the reflected lights be orthogonally rotated in order to get autocompensated ?
thanks in advance.

regards,
--islahna

 

[azntoon]

Yes, using a mirror/reflector can help to compensate polarization fluctuations, but the reflected light must be orthogonally rotated in order to get the auto-compensation. Faraday mirrors are designed to do this, as they have a special coating that rotates the light by 90 degrees when it is reflected. Without this, the polarization of the reflected light will not be compensated and the system may not work properly.