We demonstrate the generation of counterpropagating, twin-photon pairs in the optical communication band, utilizing periodically poled Rb-doped KTiOPO4. The spectral and polarization indistinguishability of the photon pairs is confirmed through a Hong-Ou-Mandel interference measurement. At degeneracy, the photon-pair generation exhibits a broad angular distribution. Notably, the forward-propagating photon tunes with the pump frequency while the backward-propagating photon frequency remains nearly independent of the pump wavelength.