Error compensation in quantum key distribution using entangled biphoton polarization states

We consider optimal strategies for selecting optical fiber segments for Alice and Bob's quantum channels that are used for quantum key distribution by entangled biphoton polarization states. We show that the quantum bit error rate in a sifted key can be substantially reduced, even with large dispersions in the random parameters of optical fiber. To do this, Alice and Bob's channels should be designed from fibers manufactured using the same technology. The selection of the pairs of optical fiber segments should be correlated, with a correlation coefficient close to 1.