An optical splitter module (140) can be carried on a cover (120) of an enclosure (100) between a contoured surface (129) and a row of optical adapters (130). Output pigtails (165) from the splitter module (140) are routed to the optical adapters (130). In certain examples, a significantly longer input fiber (161) is routed from the splitter module (140) to a splice region (114) at a base (110) of the enclosure (100). Certain types of splitter modules (140) are mounted to the cover (120) at an angle relative to an insertion axis for a feeder cable (170). A certain type of splitter module (140) curves about a minor axis (A2) so that one major surface (142) has a concave curvature and another major surface (143) has a convex curvature.