  We produce transmission and reflection spectra of the anti-directional
coupler (ADC) composed of linearly-coupled positive- and
negative-refractive-index arms, with intrinsic Kerr nonlinearity. Both
reflection and transmission feature two highly amplified peaks at two distinct
wavelengths in a certain range of values of the gain, making it possible to
design a wavelength-selective mode-amplification system. We also predict that a
blend of gain and loss in suitable proportions can robustly enhance reflection
spectra which are detrimentally affected by the attenuation, in addition to
causing red and blue shifts owing to the Kerr effect. In particular, ADC with
equal gain and loss coefficients, is considered in necessary detail.
