A new analytical approximation for photonic array modes is presented. We consider the specific class of one-dimensional (1D) photonic crystals (encompassing large arrays of coupled identical planar waveguides, large arrays of identical phase-locked lasers, etc.), in which light propagates along the optical axis of the device. Approximate analytical expressions for the array modes (both spatial distribution and propagation constants) become available. This approach allows a fast, simple, and accurate analytical evaluation of the electromagnetic field in 1D photonic crystal devices.