Coupling of spot-size converted laser diode to polymeric waveguide with 45-degree micro reflection mirror for optical surface mount technology

Low loss optical waveguides with a 45° micro reflection mirror are the key to optical surface mount technology (O-SMT), which was proposed to provide a possible solution to growing serious problems in opto-electronic product manufacturing processes. This paper presents an experimental and theoretical study of optical coupling between a laser diode placed on a board surface and a polymeric channel waveguide through a micro-mirror. The laser diode applied here has a built-in spot-size converter which enables a narrower beam divergence than conventional laser diodes. It is clarified that the 45° reflection mirror has a useful function of changing the beam direction from the vertical to the horizontal and vice versa, and passive alignment for positioning laser diodes can be applied in O-SMT