| 摘要 |
PURPOSE:To easily increase the multiplicity in the wavelength split transmission, by forming at least a part of the light input/output circuits as a light waveguide line on the substrate. CONSTITUTION:The example of execution in the figure is an example showing the constitution of a light branching filter for receiving, of multiplicity 2. A light beam which is projected from the core C3 of the optical fiber F3 and has become a parallel luminous flux by the lens L1 is reflected by the diffraction grating G1, becomes a focusing light beam by the output lens L2, is coupled with the light waveguide lines W1, W2 which have been formed on the substrate S1, and are coupled with the cores C1, C2 of the output optical fibers F1, F2. In this case, the space of said waveguides in the fiber side is wider than that in the lens side, and it is possible to reduce remarkably the degree which makes the transmission band width DELTAlambda and the center wavelength space lambdas depend on the outside diameter of the optical fiber, and the diameter of the core. |
