国家重点实验室 How to polarize:Basic module Combine two copies of W x2=4G2 w, W(y,yl4,4)=W(y4田4)W(y22） oand split to create two bit-channels W-:U1→(Y1,Y2) W+:U2→(Y1,Y2,U1) 12How to polarize: Basic module Combine two copies of W and split to create two bit-channels 12 2 1 0 1 1 G        2 2 1 12 x u = G ( ) ( )( ) 2 12 12 1 1 2 2 2 W y y, | uu W , = ⊕ y | | u uW y u