<p>Three components are aligned collectively using one light quantity monitor without aligning two components individually when an input array and an output array are connected with a waveguide chip. When an arbitrary lamination interface reflecting light in the waveguide chip (10) is a reference surface BS, and a translucent region adjacent to the reference surface BS is a reference translucent layer BL, the input array (20) is fixed and the output array (30) is moved up and down and the vertical position of the output array (30) corresponding to the reference surface BS is detected based on the height and the light receiving intensity of the output array (30). Subsequently, the vertical position of the input array (20) corresponding to the reference surface BS is detected by fixing the output array (30) close to the height of the reference surface BS and moving the input array (20) up and down. The input array (20) and the output array (30) are moved to the right and left in accordance with the height of the core (14) of the waveguide chip (10), and rough alignment is performed based on the light receiving intensity followed by precise alignment.</p>
