All‐Solid Near‐Infrared Light‐Induced Self‐Written Optical Waveguides and Optical Self‐Coupling

Abstract

In recent datacenters, considerable data communication has been performed between servers and storages; therefore, an optical interconnection with a wider band is required. Silicon photonics has attracted attention as a technology that places optical engines closer to switch application‐specific integrated circuits and realizes broadband optical interconnection. To utilize silicon photonics, it is necessary to overcome high‐precision alignment between silicon waveguides and single‐mode fibers (SMFs) having vastly different mode field diameters. Optical self‐coupling using light‐induced self‐written (LISW) optical waveguide technology is a potential solution. Previously, near‐infrared (NIR) LISW optical waveguides are fabricated using an SMF with an approximate 10 μm core through irradiation with 10 μW NIR light (1310 and 1550 nm). However, the cladding is liquid, which motivates to fabricate all‐solid LISW optical waveguides. In this study, all‐solid NIR LISW optical waveguides are produced using a core‐selective polymerization method, and single‐mode LISW optical self‐coupling between two SMFs is realized. To enhance the performance of the waveguides, additional resins are incorporated into the high‐refractive‐index base monomer during the cladding formation process. Through the experimentation, the potential for achieving even greater loss reduction by optimizing the hybridization between the base monomer and the supplementary resins is demonstrated.