Optical connecting devices fabricated by self-written waveguide technology for smart optical interconnect

Recently the importance of optical interconnect is increasing particularly in board-to-board interconnection. The success of smart optical interconnects for practical use strongly depends on the development of sophisticated coupling technologies achieving both high coupling efficiency and easy alignment. One promising technology for solving these problems is self-written waveguide (SWW) method which uses light-curable resin. This method is flexible and may allow substantial advances in the practical application of optical interconnect technology. We fabricated a micro 90 degrees light-path converter on the top of MT connector. Four channel SWWs are fabricated by irradiating a blue laser beam (406nm wavelength) from a multi-mode fiber in light-curable resin. The SWWs are covered by cladding resin. This converter is useful for connecting between fibers and an optical wiring board. We have further developed this fiber-SWW technology into a new technology we call the "Mask-Transfer SWW method". The Mask-Transfer SWW technology involves contact exposure of UV-curable resin through a photomask. Alignment of the photomask pattern with the target can be precisely accomplished by employing a conventional mask-aligner. We proposed a new V-grooving method by applying the Mask-Transfer SWW method. V-grooves are a well-known technique for aligning optical fibers for coupling. Unlike the conventional methods and material, this new method has an advantage that V-grooves can be easily fabricated precisely on various kinds of substrates as designed. Therefore, optical coupling between fibers and devices is achieved simply and efficiently. We believe that these devices will be a key for smart optical interconnects in near future.