  Cosmic string wakes produce direct B-mode polarization at leading order in
cosmological perturbation theory, as worked out in a previous publication
\cite{BDH} in the case of a single string wake. Here we compute the angular
power spectrum of B-mode polarization from a scaling distribution of string
wakes. We find that the averaging which enters in computing the power spectrum
renders the signal, which is distinctive in position space maps, too small in
amplitude to be detectable with the first generation B-mode surveys. In
addition, the spectral shape is similar to that of gravitational lensing,
making it additionally difficult to detect the cosmic string signal from the
angular power spectrum. Hence, a more promising way to constrain cosmic strings
using B-mode polarization is by analyzing position space maps using novel
algorithms such as the Canny algorithm.
