  Solving the Schwinger-Dyson equations, we analyze the pairing of quarks in
asymmetric quark matter where quarks have different chemical potentials. We
show that in the asymmetric quark matter a crystalline color-superconducting
gap opens when the quark coupling is stronger than a critical value. The
critical coupling is nonzero, since the infrared divergence is lessened when
the momenta of pairing quarks are not opposite. The superconducting gaps and
the critical couplings are calculated both at high and intermediate densities.
