Interferometry with quantum states of light has been an active research field for several years. Interference patterns with reduced broadening due to spectral dispersion can be obtained using entangled photons produced by the nonlinear optical process of spontaneous parametric downconversion (dispersion-cancellation effect). Here we describe two new interesting effects. The first one is a new quantum optical interferometer which separates the odd- and even-order spectral phase terms in two distinct subregions of a global interferogram. The second effect is the insensitivity of quantum interference to even-order aberrations (e.g. astigmatism) when working with spatially-anticorrelated entangled photons.