Passive alignment of single-mode fibers to integrated polymer waveguide structures utilizing a single-mask process

A fabrication process for high precision passive fiber chip coupling is presented. The difficulties of structuring highly nonplanar surfaces were solved by using an electrophoretic photoresist and introducing additional structures to prevent wide holes. The method involves only a single lithographic step for structuring the polymer waveguide and fiber aligning structures in Si and thereby minimizing the horizontal displacement. The loss due to fiber displacement is about 0.7 dB per front face.