Photopolymer-based three-dimensional optical waveguide devices

Photopolymer based three-dimensional (3D) waveguide devices are very attractive in low-cost optical system integration. Especially, Light-Induced Self-Written (LISW) technology is suitable for this application, and the technology enables low-loss 3D optical circuitry formation from an optical fiber tip which soaked in photopolymer solution by employing its photo-polymerization due to own irradiation from the fiber tip. This technology is expected drastic mounting cost reduction in fields of micro-optic and hybrid integration devices assembly. The principle of the LISW optical waveguides is self-trapping effect of the irradiation flux into the self-organized waveguide, where, used wavelength can be chosen to fit photopolymer's reactivity from visible to infrared. Furthermore, this effect also makes possible grating formation and "optical solder" interconnection. Actually fabricated self-written grating shows well defined deep periodic index contrast and excellent optical property for the wavelength selectivity. And the "optical solder" interconnection realizes a passive optical interconnection between two faceted fibers or devices by the LISW waveguide even if there is a certain amount of gap and a small degree of misalignment exist. The LISW waveguides grow towards each other from both sides to a central point where the opposing beams overlap and are then combined into one waveguide. This distinctive effect is confirmed in all kind optical fibers, such as from a singlemode to 1-mm-corediameter multimode optical fiber. For example of complicated WDM optical transceiver module, mounted a branchedwaveguide and filter elements, effectiveness of LISW technology is outstanding. In assembling and packaging process, neither dicing nor polishing is needed. In this paper, we introduce LISW technology principles and potential application to integrated WDM optical transceiver devices for both of singlemode and multimode system developed in our research group.