A first array of microlenses (16) on a lens substrate (15) is accurately aligned with a lens holder (20) by making a second array of microlenses (17) simultaneously with the first array. The second array of microlenses is arranged around the periphery of the lens substrate and is made solely for alignment purposes, rather than for focusing light. An array of detents (21, FIG. 2) is made in one surface of the lens holder such that, when the lens holder is abutted against the lens substrate, each microlens (17) of the second array can extend into one of the detents of the lens holder member, thereby to align the first array of microlenses with the lens holder member. The lens holder member has an opening (22) to permit light to be transmitted to or from the first array of microlenses (16). A pair of alignment pins (24) aligns the lens holder member with an array of optical fibers (12).