In this work we consider a dipole asymmetry in tensor modes and study the
effects of this asymmetry on the angular power spectra of CMB. We derive
analytical expressions for the $C_{l}^{TT}$ and $C_{l}^{BB}$ in the presence of
such dipole modulation in tensor modes for $l<100$. We also discuss on the
amplitude of modulation term and show that the $C_{l}^{BB}$ is considerably
modified due to this term.Comment: 12 pages, 5 figure

Zarei, Moslem