Manabu Kagami, Tatsuya Yamashita, Akari Kawasaki

In order to simultaneously realize high-speed data transmission, low-cost and a lightweight network in automotive applications, a wavelength division multiplexing (WDM) optical communication system has been considered to be a suitable solution. We developed a light-induced self-written (LISW) waveguide technology for a three-dimensional (3-D) optical module fabrication. This technology utilizes the selective polymerization of photo-polymerizing resin blends and the self-focusing phenomenon of the optical fiber's outgoing beam by a refractive index increase in the material hardening process. When an optical fiber is soaked in two kinds of photo-polymerizing resin blends in which the hardening wavelength differs (l> l₂), and then the resin is irradiated withl light through the fiber, a hardened polymer waveguide having a uniform diameter geometry would grow from the fiber tip. This method does not need any fiber alignment and packaging process; therefore, cost-effective module fabrication can be expected. We also confirmed two key component formations necessary for the 3-D WDM module: regrowth of the waveguide from the backside of a WDM filter after passing through it, and a 90¡ reflected waveguide using a 45¡ mirror. Finally, we proposed the module structures for a bi-directional and WDM application.