  In this paper, we study the effects of instrumental systematics on the
reconstruction of the deflection angle power spectrum from weak lensing of
Cosmic Microwave Background (CMB) temperature and polarization observations. We
consider seven types of effects which are related to known instrumental
systematics: calibration, rotation, pointing, spin-flip, monopole leakage,
dipole leakage and quadrupole leakage. These effects can be characterized by 11
distortion fields. Each of these systematic effects can mimic the effective
projected matter power spectrum and hence contaminate the lensing
reconstruction. To demonstrate the effect of these instrumental systematics, we
consider two types of experiments, one with a detector noise level for
polarization of 9.6 uK-arcmin and FWHM of 8.0', typical of upcoming ground and
balloon-based CMB experiments, and a CMBPol-like instrument with a detector
noise level for polarization of 2.0 uK-arcmin and FWHM of 4.0', typical of
future space-based CMB experiments. For each systematics, we consider various
choices of coherence scale. Among all the 11 systematic parameters, rotation
and monopole leakage place the most stringent requirements, while quadrupole
leakage, pointing error, and calibration are among the least demanding. The
requirements from lensing extraction are about 1-2 orders of magnitude less
stringent than the requirements to measure the primordial B-modes with
inflationary energy scale of 1.0*10^{16} GeV. On the other hand the
requirements for lensing reconstruction are comparable or even more stringent
for some systematic parameters than the requirements to detect primordial
B-modes with inflationary scale E_i = 3.0*10^{16} GeV.
