Patent ID: 7221830

Claim:
An optical transmission module connecting method for performing alignment of an input side optical fiber array, an output side optical fiber array, and an optical transmission element including at least one of a lower substrate, a core, a cladding, an adhesive layer and an upper substrate in the interior thereof, and connecting their cores, comprising: making a first collimated beam incident on an output side end face of said optical transmission element and taking an image of an input side end face of said optical transmission element to detect the position of the core at said input side end face; making a second collimated beam incident on said input side end face of said optical transmission element and taking an image of said output side end face to detect the position of the core at said output side end face; detecting the position of a core of said input side fiber array and a core of said output side fiber array at their respective connection portions; and positioning the core of said input side fiber array at its connection portion and the core of said optical transmission element at its input side end face, and the core of said optical transmission element at its output side end face and the core of said output side fiber array at its connection portion respectively, wherein a first incidence angle is formed by said first collimated beam and a line orthogonal to said input side end face of said optical transmission element and a second incidence angle is formed by said second collimated beam and a line orthogonal to said output side end face of said optical transmission element, such that said first and second collimated beams introduced into the interior of said optical transmission element each are totally reflected at least at either one of boundary surfaces of the core and the cladding.