| 摘要 |
PURPOSE:To provide a multi-position directive coupler, which is excellent in productivity and reliability, by laminating a photosensitive resin having a thickness of several 10 to 100 microns upon a flat substrate having a lower refractive index so that a pattern of the resin is formed to constitute the core of an optical waveguide. CONSTITUTION:A photosensitive resin is uniformly applied to a quartz substrate 1 and exposed to light so that it may be set. Then, the resin is etched to constitute a circuit, thus producing a multi-position directive coupler. The joint between a main waveguide 2 and an auxiliary waveguide 3 is common to joint optical fibers 6, 7, 8 and 9 so that a thermoset transparent resin 4 having a lower refractive index than the photosensitive resin covers the main waveguide as a whole and is set to constitute an optical coupler. The optical signals from the fiber 6 at a terminal T1 are transmitted through the waveguide 2 so that a portion appears at a terminal T2 whereas another portion appears at a terminal T3, while connecting the waveguide 3, until it is transmitted to the fiber 8, but it does not appear at a terminal T4. Thus, the optical coupler can enjoy excellent productivity, and the circuit construction can be optimized easily with high reliability so that the adaptability to the multi-position optical fiber can be improved. |
